<...> Added 'Users Online' <...>
I was just focusing on the number of Bitcointalk active users, and you make it 611 (presumably K) profiles. That number alone is near the sum of all non-newbie profiles, and many of those are not active at all, nor have been for years. Since active is not a universal term (you could consider active in the last 3 months, six months, a year and so on), there should be a definition of what is being considered as active, making sure it is the same definition across all three compared platforms to make the comparison feasible.
I was also wondering:
- Where do ex-bitcointalk banned users go after ban? 
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Either they quit for good, or they resurrect on the third day and start from scratch, probably wasting their time as they may be caught for ban evasion.
Sure, I will update if I find statistic like that on alternative forums.
I think that resurrection is 100% certain fact, as there is Unban option in Bitcointalk forum