At a panel at the end of this year's New York Comic Con, ReedPop, the company that organizes the event, reported that it sold 151,000 tickets this year.
This means that New York Comic Con is now the biggest pop culture event in North America.
San Diego Comic Con has had to cap it's attendance at 130,000, due to capacity issues at the San Diego Convention Center. NYCC actually surpassed SDCC in attendance last year as well, with 133,000 attendees. Most seem to consider the 3,000 person difference to be close enough to call "even" (because math works that way, I guess?), but it's pretty hard to ignore a 21,000 person gap.
NYCC met capacity problems at the Javitz Center, similar to SDCC's problems, last year, but ReedPop solved this problem by extending the convention for another day, opening on Thursday instead of Friday. This allowed for another day's worth of ticket sales.
It will be interesting to see how ReedPop handles such immense growth at the convention going forward.
The next New York Comic-Con has already been announced for October 8-11, 2015.