Now if this BitcoinTalk forum is not allowed to conduct any kind of signature campaign, will everyone be active in this forum as it is now? No one posts here without profit, everyone has a signature code on their account, there are only a handful of people left.
Its only Mixer campaigns which are getting banned, its a decision which has been made,
its not a requirement "yet", its like a preemptive decision in order to preserve the forum as
an entity. Here is the first paragraph from the announcement.
Bitcointalk.org aims to allow about as much freedom as is reasonably possible. But this is not a darknet forum, and with mixers looking "grayer and grayer", it's no longer reasonably possible to allow linking to mixers. Even though "a cryptocurrency mixing service is not necessarily illegal," a clear pattern has emerged where mixers pop up, last for a little while, and then get taken down by law enforcement once they get too big. Allowing mixers to be posted on bitcointalk.org before they seemingly-inevitably get declared illegal and seized is not sustainable. Therefore, promoting mixers will no longer be allowed, similarly to how darknet sites are already disallowed.
As regards the altcointalk forum and people switching their activity to that maybe
these scenarios will happen:
a.) Only a minority will move their activity and there wont be a "brain drain" to affect BCT
because most of the top quality posters will remain here.
b.) Because of point a. above those who initially move to ACT will eventually migrate back
to BCT because this is where the vast majority of active members and general chat will remain.