User blog comment:ReturnofDreggmanRox/Haven't Been Here in 4 and a Half Years/@comment-4533965-20170312055207

Oh boy, four years? Alright man, grab some popcorn. About to deliver you a story.

So 2013 was four years ago, obviously. Sonic Lost World was released, new templates and a ton of articles were created during this time. Forums are no longer a thing; they've been replaced by threads. The chatroom was quite packed with more users than ever, but by September 2015 the social users (the users who only came on the wiki for the chat room) had left to a private Skype group, which was then transferred over to a Discord group chat. Since then, the chat room functionality has been essentially dead, and whatever conversations occur on this wiki are now on that Discord chatroom. Activity dwindled down following Sonic Boom's release and the disaster that ensued. Since then, the wiki has lost a significant amount of users. We reached 10,000 articles on September 2015 to the current number of articles we have now.

So really, you haven't missed a significant change in the wiki other than the amount of users that come on the wiki regularly.