So, apart from here in bitcointalk, has any other forum or website adopted the signature campaign system of advertisement?
Yes, there is one forum I was once about that adopted a signature campaign advertisement system but it seems to stop at some point.
Bitcointalk appear to be the only forum that is successful in the signature marketing area due to the forum being the harness for new and old crypto-related business to announce their establishment, advertisements, etc. I could remember Binance once hard their bounty campaign here.
Does theymos have a patent for signature campaign such that no other forum can replicate what is happening here without his permission.
No. I think the reputation of this forum
which is built on community-driven and the legacy of Satoshi is what makes it impossible for any other forum to replicate what Bitcointalk is doing.