The only time I'm faking the actors is for the fake interviews.
If you take a faker and have them pose as one of the actors on the forum - which you can if the mood strikes you - it is to be assumed that it's a fake fake acct and that the test should wank about it.
If you are commenting to such a post. Some should BELIEVE. Some should believe it's at least possible if not that particular name is true. Some should not believe but not care. Some should HATE it and get ips and post huge things about how it isn't the actor.
Joe Flanigan, danneel and other verified twitter accounts will not be faked screenshot. Your posters can comment things like "Joe says he's home. So they must have wrapped ep#" and a fake link.
But the actors never participate in the online blogs or forums in my world. They comment about them as at least two of the producers keep printing out things for them. But they don't seek it out.