PTT is still heavily used in Taiwan by university students. The numbers today might not be quite as high as the quote from Wikipedia below (due to the rise of Facebook), but the system is definitely still extremely active.
"PTT is arguably the largest BBS in the world with more than 1.5 million registered users. During peak hours, there are over 150,000 users online. It has over 20,000 boards with a multitude of topics, and more than 20000 articles and 500000 comments are posted every day."
http://en.wikipedia.org/wiki/PTT_Bulletin_Board_System