If he has, do you know his user name?
Answer on Does T.O.P from Big Bang have twitter?
TOP doesn't have a twitter, Taeyang is the only Big Bang member so far who has one, and his account is: http://twitter.com/Realtaeyang
For more Kpop idols' twitter accounts you can check this site for all their usernames, it's very accurate and updates on new ones all the time: http://aa-chan.net/blog/follow-fandom#ko…
TOP does have a me2day account which is something similar, it's all in Korean though but it's the only social networking site I know he's on: http://me2day.net/topofbb