Would you consider it cloaking to let google bots into a members only area of a forum? So basically, when you click on the google search results, the forum asks you to sign in to see the thread. Has anyone been penalised for this?
what you're referring to isn't really cloaking... and i don't think anyone has been penalized for that.
I will refer you to this thread: http://forums.digitalpoint.com/showthread.php?t=904320 There is a risk of the private forum threads showing up in the search index and cached pages.
if your private forum contains private info, there is really no reason why you would want google to index those pages. if you don't mind people bumping into your posts, you could use .htaccess to allow google bots
I think its just normal, but make sure they have the option to turn it down or accept the registration.
I don't think you can be penalized for that. But yeah just make sure they don't have to register. Give them the option to view the post without signing up.