which is the largest?
ResetEra is another big one. I've seen anywhere from 1,000 to 10,000 online users at once. Usually around 3,000.Depends how you define popular. For example by users online, IGN is more popular than NeoGAF. There are other Xenforo forums with an even higher concurrent user count, but feature "unacceptable content", so I won't be linking those.
A good list. Few forums in this list I already used, but I never noticed that these are also Xenforo as they have totally different theme and no signature in the bottom.This is a list of large forums running XenForo software. To be added to this list, there must be a minimum of 1,000,000 posts and the forum must be publicly accessible. Sites related to unacceptable content such as gore, pornography, warez, etc. are not eligible. If you would like your site...xenforo.com