Assuming sometime back in the Paycoin days from what I got from it, maybe even earlier.  Then there's Derek Broyhill, who lurks under many different names and always seems to know what is going to happen and tries to steer the 'community' towards it.

Also sciborg/FollowBTCnews has been very active at times.  Krumz, Xeohash, Dkbay, modcom, GTR_JOEY...the list of ION guys involved in one way or another goes on and on.  Tippy will explain.

Edit - can confirm even just users are now being banned for asking legit questions