[G]Introduction to watching Competitive DotA/DotA2

Many players of LoL or lower level DotA/Hon would argue that there exist another hero role labeled as “tanks”. Their existence is a delusion perpetrated by low level players to justify playing carry heroes without getting any survivability. While heroes can be “tanky” and there are certainly strength based carries/semicarries that are inherently resilient along with agi/int heroes who focus on survivability items with their farm. But the only actual hero that fits the role of “tank” in its D&D roots is Axe, a low tier hero generally unused in competitive play.

TL DR: "Get a tank = retarded"

Supports are generally heroes that have many of the following characteristics
-Strong in the early phases of the game
-Don’t require much farm to be effective
-Use disables or other utility spells to gank or teamfight
-Have large teamfight spells that can influence large scale battles
Some of the top supports in the current roster are:
VS, CM, Lich, Tidehunter, Earthshaker, Venomancer, Lion
Almost all of these heroes have a nuke/disable that is extremely powerful in the early game, support skills that benefit the team, and ultimates that can greatly influence the course of the game. While some pure supports (5th position) such as VS and CM don’t need anything besides boots and wards, some supports (4th position) require mid tier items to reach their full potential (Blink for Tide/ES and Vanguard for Veno)
One of the roles of supports is to affect the outcome of the laning phase by either babysitting (staying in a lane to help harass opponents and deny creeps) or by ganking (travelling to attempt to kill enemy heroes).
Another key duty is warding and counterwarding, vision is probably the most important thing a support can offer for the team by providing intel on enemy movements as well as deny the enemy the same through counterwarding. The state of a game can often been seen by the wards of both sides; of how many and how offensive/defensive wards are up for each team and the areas in which they have vision.
Some other duties in the early game involve constantly carrying tps and moving to aid teammates, stacking jungles (creating additional spawn for the carries to kill later).
During the mid and lategame, supports are expected to continue to ward/counterward while doing whatever is needed of them. They are expected to continue ganking, respond to threats to carries, and participate in teamfights.
Any superfluous farm obtained by supports are expected to go to either wards, core items (as labeled above), and “team items” (Mek, Drum, Pipe, Pushstick, etc.)

While their roles in the early game are similar, the midgame played by 2nd and 3rd position heroes different greatly with the lineup. During the early game, these heroes are usually expected to stay in their lane to accumulate farm and exp.

Gankers gonna Gank, simply put, the main goal of these heroes is to disable and kill enemies
Some of the top gankers in the currently lineup include
Beastmaster, Clockwerk Goblin, Storm Spirit, Puck, NS
In general, gank heroes need a certain degree of farm (IE. Vanguard + blink for BM) to be extremely effective. Upon obtaining a certain amount of levels and items, most gank heroes are capable of appearing out of nowhere and solo killing opposing support heroes and carries with help with 1-2 other heroes during the midgame. During the late game, many of the ganking heroes lose a certain degree of effectiveness, but their ability to initiate, hard disable, as well as tank and dps to a degree.

Semicarries are used in conjunction with or in lieu of hard carries. They tend to be ranged heroes that are either very strong or resilient in the laning phase, can farm fairly well, and scale quite well in terms of providing dps for the mid and late game.
Some of the most commonly used semicarries are
WR, Storm Spirit, Weaver, SF, PotM
Depending on the lineup, the midgame role of semicarries is often to pressure lane and to actively engage in teamfights while farming, often alleviating pressure from other lanes by providing significant threats to the other team while being difficult to gank with less than 3 heroes. Depending on the farm, it is not surprising to see semicarries take over games by being allowed to freefarm while a team focuses on pushing or ganking the carry.

Carries are heroes that, in the classical game of 2010, “win games” by farming and engaging with overwhelming might upon obtaining sufficient levels and items.
The undisputed top 2 hard carries in the pool are Spectre and Morphling, though I believe that we might see quite a bit of Antimage as a hard carry during Gamescon
The traits shared by these heroes are
-Difficult to gank
-Scales extremely well with levels and core items
-Capable of outputting absurd amounts of DPS
Indeed, when a Spectre finishes its basic core of vanguard + radiance, merely casting its ulti will often bring the opposing support heroes down to half health. If carries from opposing teams both become farmed, much of the game will hinge upon key engagements between the titanic forces in key teamfights.

The 3-1-1 setup was the standard during late 2010, the concept was fairly simple, use a resilient hero such as WR to solo against 2 opposing heroes without dying, and crush the other 2 lane with 3 heroes, often ones with strong early game nuke/disables and create farming space for hard carries.
A pair of 3-1-1s matched up against each other will often result in very explosive early games with constant action from the lane, which will often decide the game. However, a pair of 3-1-1s matched against solos will often result in the extreme farm games which had been associated with Chinese dota, as both of the solo heroes will be essentially crippled as hard carries on both sides obtain freefarm.

The 2-1-2 was the de facto standard before the existence of trilanes and has seen a revival of sorts in recent times, due in large part to the popularity of heroes such as Weaver or Lich, who were capable of facing trilanes, alone or in pairs, without fear of constant death and with opportunities for decent amounts of experience.
The standard for the 2-1-2 was to have a Gank/Semicarry mid, with the sidelanes taken up by a support and a hero that requires farm. This setup leads to fairly standard laning phases with relatively even matchups, with the outcome largely dependent upon the laning skill of individual players.
When matched up against a trilane, the key to look for is the amount of disadvantage in the 3v2 lane and in the 2v1 lane, which tend to create radical imbalances in the level/farm of various heroes that greatly affect the midgame.

This lane setupid grew out of the trilane when it was realized that merely the threat of a pair of heroes would often discourage the solo hero from moving away from the tower against a trilane, freeing up supports that could otherwise gank at will or farm the jungle.
With heroes like Chen or Enchantress, heroes that were capable of farming the jungle normally while threatening ganks, a new style was created to take use of the 4th lane, and the jungle hero and often a support stay farming in the jungle while constantly threatening ganks on the lane, effectively creating a similar amount of pressure to a trilane without falling behind on levels and farm.

With the standard game being dominated by carries, most teams without either a definite hard carry or semicarries usually fall into push or gank lineups.
A push lineup is often made up of two or more of Furion, Chen, Engima, Venomancer, or Enchantress along with Int based pushing heroes like Omiknight, Nec or Pugna. These lineups rely on heavy pushing during the mid game and is often all-in in nature due to an inability have strong physical dps in the late game.
A gank lineup is simply made up more of the standard gankers and more gank-oriented supports than usual. Any team with large emphasis on running heroes like NS. While not quite as all-in as gankers can scale decently with an item advantage, it is still imperative
To obtain said advantages before the opposing carries become developed.

The first phase of the game typically involves heroes from each team spreading out to each of the three lanes (or the jungle) in some combination. The goal of the laning phase is to gain basic experience and items.
Depending on the lane matchups, this phase of the game can be either wildly exciting (3v3 lanes) or rather passive (3v1s), with mid usually being fairly pivotal, as the hero that is capable of gaining an advantage in mid through levels, farm, or rune control can have huge impacts on the sidelanes.
Supports can be ganking frequently but do not always do so, but the cores rarely leave the side lanes. The end result of the laning phase can usually be seen just by looking at hero levels/deaths/creep kills are is fairly easy to judge.

The midgame usually occurs after a few of the outer towers have fallen, forcing heroes away from the safety of their towers. Ganks, small scale teamfights, and pushes occur quite frequently during this time, with each small engagement changing the state of the game.
During this time, supports and ganks will rarely stay in lane but rather actively wander the map looking to advance the game plan.
Many strategies, such as Gank/Push based ones, rely on full execution during this phase to score a large advantage in either the number of hero or tower kills, failure to secure this advantage can often be the downfall for such lineups as the lack the raw power to go head to head with hard carries.

Lategame is often signified by the removal of a majority of outer towers, assault on base towers, of the completion of certain core items on carries. During this phase, major 5v5 engagements are the norm, as getting any hero picked off can result in a severe disadvantage in a teamfight or potentially a lost set of barracks.
Roshan often becomes decisive in this phase of the game, as securing Aegis or Cheese can result in a huge advantage in the next teamfight as well as a decent amount of gold for the team. Teamfights are usually triggered by pushes, Roshan, or gank engagements, with each being able to wildly affect the game. These teamfights often come down to a combination of farm, coordination, and execution and are epic sights too see.

Aside from kills, level can tell us which heroes are doing well at a glance, any hero with close to the 1lv/minute mark midgame can be said to be doing extremely well wheras a support hero who’s level 9 30 minutes into the game tell the opposite.
Along with basic “who’s doing well”, having the leveled up ults for heroes such as ES or Tide is also extremely important timing wise and is a good indicator as to which team has been getting the upper hand in teamfights.

Farm is perhaps the most important indicator to the state of the game, which can generally be seen by a simple cs/kills/death analysis as to which heroes are doing well in farm.
It is also important to keep track of certain items on certain heroes, for example, Spectre only becomes truly scary once she obtains radiance and ES is only a huge force in teamfights once he grabs that blink, noting key item pickups will help you see relative strengths of teams and timings.
Attention should also be paid to each team’s “teamfight” items in the form mek, drum, pipe, vlads, push stick, and shivas, these items have effect much greater than their cost in 5v5 situations and are often deciding factors during midgame teamfights.
Finally, carry farm should be compared, the easiest way to compare carry items is the number of high tier equipments, however, keep in mind that certain heroes scale better than others in terms of items. For example, an Antimage with only 2 high tier items might be stronger in terms of damage output than a PotM with 3 simply because he scales much better lategame.

Tower kills represent not only a significant gold boost, but also loss of map control and vision. Each tower kill decreases the amount of the map the team can control with vision and the ability to support allies with TPs
However, it must be noted that simply pushing down towers without gank presence or ward vision may often yield actually additional farm space for opposing heroes as the lane is more often on their side of the map where allied reinforcement is difficult.
With push lineups, the number of remaining outer towers can be a counter to a decisive teamfight, generally, if a pure push team is capable of pushing down a pair of rax before the opposing carry has its first high tier item, they are doing fairly well.

While their value has been slightly diminished by the advent of Smoke, wards are still the single best item in the game (except for maybe thunderhammer). The number as locations of wards can often give a great idea as to how the game is going for both sides.
In the early game, wards are generally placed to do the following
See the rune
Deny the opposing jungle
Protect key lanes/heroes from ganks
The lanes are heroes being protected can give a decent idea as to which heroes are placed in higher regard and will be allocated more farm.
Past the early game, the wards tell a much better story. Offensive wards, usually placed behind the enemy towers or in the opposing jungle, mark the area controlled by the opposing team and the restrictions on the defending team’s farm while defensive wards highlight areas safe for farming. If a team is huddled in their base with little outside vision, they are limited in the amount of farm and map control and are often on the way to losing a game.

The first hero (usually a gank or a support) to engage the opposing team in a teamfight, this is usually done with a strong ulti that can deal either large amount of aoe damage/disable or one that isloates or disables a single target for the team to jump on
A few of the top initiators are: Clockwerk (ulti), Vengeful Spirit (ulti), and Earthshaker (blink + ulti)
Many of the top initiators can also be held back as counter-initiators, as focusing fire upon one enemy or following up on initation can often make your own team formation falter and be in prime position to be counter-initiated on.

Heroes with aoe nukes are expected to simply expend them as cooldowns expire to deal damage to as many enemies as possible, especially clusters of fragile enemies or batches of summons. Since heroes with this role tend to be fragile caster/support heroes, their positioning and spread is very important throughout the battle. Some of the best sustained Aoe Dps comes from Heroes like Nec, Pugna, Lina, and Windrunner

Disables often accompany Aoe dps but often has different targets when used for the disable rather than the damage. These are usually chained so as to keep a single enemy incapacitated for as long as possible as the team focus fires it down or to keep tougher heroes out of the fight while weaker ones are killed. The choice of hero to focus is determined by the team but is usually either the hero with the highest threat/survivability ratio. Single target nukes work in much the same way, to help aid the murder of the hero deemed by the team to be focused on.

Aside from damaging spells, there are many supportive spells that can greatly affect the tide of battle. For the sake of simplicity and uncaring attitude towards semantics, I will include the use of teamfighting items such as Mek or Pipe as "support spells".
Support Spells tend to be either set ups or reactionary. Their use can often save a crucial hero or allow one to vastly increase their damage output. Two of the most powerful set up spells, Punga's nether ward and AA's frozen sigil, greatly affect the positioning and outcome of a teamfight. They essentially change the playing field with their effects.
Conversely, reactionary spells like using VS swap or heals to save a dying teammate can also change the flow of battle. By using reactionary support skills to disrupt the enemie's gameplan, you can break down the organization of the enemy team and exploit the chaos. The teamfight at the 52nd minute of the second video showcases the power of such skills in a crucial teamfight.

Usually performed by the carry or semicarr(ies)y, physical DPS is what teamfights often come down to if one side doesn't obtain a major advantage such as killing a hero outright or completely breaking the formation of a team through setup and initiation. Since all the frequently used carries in the current metagame (ie. antimage and Spec), are both very mobile, their choice of action as to either focus fire with the team or go straight for vulnerabilities at the back of the enemy formation is a critical one.

Before a teamfight ever even happens, several things should be crossing you mind.
The first is the state of the game, which team is at an advantage, did any hero just finish some sort of large item/get a certain level, how farmed are the carries, etc. This should allow you to perform a strength assessment of both sides. You should also analyze the effect the teamfight can have to this balance a crushing teamfight near roshan for a team already in the lead might lead to a team getting roshan, gaining a huge level/gold lead, and push down a lane while the same for the opposite team may merely even out the score
The second thing to consider is the cause of the teamfight, and which team is forcing the fight. The easiest ways to force a teamfight are attempts at Roshan and the pushing down of base towers, while both will nearly always force a response from the other team, the team forcing the fight is often at a disadvantage in terms of terrain, towers, or roshan bashing people's face in.
The final thing to note before the fight even takes place is the team formations, which can often give a good idea as to the team's plan during the teamfight. For example, a formation with a hero like a Tanky Doom leading the way with a Blink ES in the back probably expects to bait the enemy into a battle with Doom as the spearhead and counter-initiating with ES.

PICTURES (didn't have internet when i wrote this so i'll get some at some point)
Better organization (probably when i'm not silly)
More games (Somebody tell me some good ones with westerning teams without Sylla/Lycan)
MOAR ACTUAL KNOWLEDGE STOP SUCKING(meh)
Less Chinese bias (but Chinese dota is Best DotA)
PS. + Show Spoiler +