There appears to be zero security on the passwords as they were stored in plain text (really GOM?). This means if you use your GomTV password anywhere else, you should change it and consider it compromised. To clarify, your GomTV.net username, email address, PayPal real name and your GomTV.net password are likely compromised. Personal information such as your address may be compromised too if it was stored. You should also change your GomTV password to prevent unauthorized account access, although the exploit through which the information was compromised may still exist.
Since payments are processed through PayPal, there is no risk of your financial information being compromised, unless you used your PayPal password when signing up for GomTV (don't do this). Users who logged in via SNS should be safe as Twitter / Facebook authentication is token based, not password based.
If you aren't already, you should really use unique passwords for each website since this happens more often than you think (ever hear someone say they were "hacked"? this is likely how it happens) and not all websites will disclose if they get compromised. Use http://keepass.info/ for password management.
UPDATE: Email from GOM:
Dear Valued GOMTV.net users:
We regretfully inform you that approximately at 2 AM KST, Aug.12th, there has been an attack against our web site, GOMTV.net.
We have found that some of the user information from GOMTV.net has been compromised from the attack. We suspect that the following information might have been exposed: name, location (country), e-mail address, GOMTV.net nickname and password.
We deeply apologize for the inconvenience and concern caused by the intrusion.
Since we use PayPal’s service to handle payments, we do not store nor have any payment related information on our site including your credit card numbers and bank account details.
We strongly encourage you to change your GOMTV.net password and if you have been using the same password for other web sites, we suggest changing the passwords for those sites as well.
Users who have signed up with Facebook or Twitter do not have to worry about changing their passwords as they did not have to enter separate passwords at the time of sign up.
As soon as we discovered the sign of intrusion we have conducted a complete investigation into the incident and have also taken steps to enhance security and strengthen our network system in order to provide you with better protection of your personal information.
We greatly appreciate your patience and understanding and we pledge to work harder to bring you a better and greater service experience.
If you have any concerns or questions please feel free to contact us at support@gomtv.net.
Thank you.
GOMTV.net
We regretfully inform you that approximately at 2 AM KST, Aug.12th, there has been an attack against our web site, GOMTV.net.
We have found that some of the user information from GOMTV.net has been compromised from the attack. We suspect that the following information might have been exposed: name, location (country), e-mail address, GOMTV.net nickname and password.
We deeply apologize for the inconvenience and concern caused by the intrusion.
Since we use PayPal’s service to handle payments, we do not store nor have any payment related information on our site including your credit card numbers and bank account details.
We strongly encourage you to change your GOMTV.net password and if you have been using the same password for other web sites, we suggest changing the passwords for those sites as well.
Users who have signed up with Facebook or Twitter do not have to worry about changing their passwords as they did not have to enter separate passwords at the time of sign up.
As soon as we discovered the sign of intrusion we have conducted a complete investigation into the incident and have also taken steps to enhance security and strengthen our network system in order to provide you with better protection of your personal information.
We greatly appreciate your patience and understanding and we pledge to work harder to bring you a better and greater service experience.
If you have any concerns or questions please feel free to contact us at support@gomtv.net.
Thank you.
GOMTV.net