That also doesn't include the idea of sponsored accounts. Where App.net or charities in rich countries buy an account for someone in a conflict zone.
You could stretch it to sound like a million dollar membership country club you want to be a part of because of all the potential investors who are hanging out there, and you want your idea heard.
The $50 entry barrier will not eliminate this problem, but reduce it a lot.
Also, didn't Dalton himself mention that this does not intent to be a twitter/facebook killer? Those channels will always exist and you can always check out trending topics if need be.
Just thinking out loud.
That sounds truly horrific if most web design conference tweets and talks are anything to go by.