Didn't they lose a lot of credibility when one of the people who used to run the site started the Yoda breaks wind in Episode III rumor?

That was mo mere rumour. That was almost in the movie.

Wasn't Yoda supposed to avoid capture by acting like a nutjob (and farting) -- so they assumed he wasn't a jedi?

Yeah it was after the attack on Kashyyyk. Right around the time when the clonetroopers have their spots on the lookout for survivors of the attack.

The other so shocking it's true was a young Solo being raised by wookies during the attack on Kashyyyk.