I just don't see the big deal. It's just a few dollars, I'd hope there was a way for people to pay without a credit card - even just posting a dollar in an envelope would do.
Why would it stop 'professionals' posting? Someone used Snood as an example, well, if the guy was going to drop in and defend himself then paying $1 is nothing. I'd certainly pay $1 to defend myself - maybe he'd be more likely to stick around and post further if he did pay.
Invite forums won't work in the above case either. What if you don't know anyone and want to post? I wouldn't want someone out of the blue mailing me asking for my approval. Too risky.
It shouldn't stop newbies either. If they're serious about going Indie then a $1 outlay should be nothing.
The case for more mods is interesting but where does it end? In a years time will we be in the same situation and need macro-mods?
Personally I'd like to avoid all the obvious questions. Things like "what program do I use to write a game?" and "how do I use an array?" are the kind of questions that can be asked at other sites. A simple $1 barrier would help cut these out.
The other point is experience, it's quite hard to know who you should pay more attention to on here. People who have never completed a game happily post authoritive opinion as if it's fact - on topics they have no experience with yet.
When I first joined the Dexterity boards I was a newbie. I had 8 years industry experience under my belt but I knew nothing about selling a game. Would be good if we had a retail\industry experience indicator, can't think of a decent way to do this though.
To those who wouldn't pay the fee - why not? Can you honestly say you haven't had one dollar's worth of value out of these forums?
Maybe there's a case for both more mods and a fee? Wouldn't this make everyone happy?