Bitcointalk.org is privately owned by theymos, basically all bitcoins donated to the site belongs to him.
I am not sure that is correct.
I know theymos is the administrator of the forum. The domain name is owned by Sirius. I own bitcointalk.
Quote from 2012:
Sirius founded the forum and still owns the domain name, so I would say that he owns it.
https://en.bitcoin.it/wiki/BitcoinTalk