I think it can be intimidating for people who feel like they can't speak authoritatively enough.

In another forum, where I'm an admin, I encourage people who post, even if they aren't sure,a nd to simply qualify what they say with 'as far as I know' or something similar. that way they don't feel the pressure of trying to be a voice of authority when they might feel they aren't qualified.

__________________
Cheers,
David