funny, i was thinking of steam's greenlight program as a barrier, although less of one perhaps then a site with a reviewing team too small to handle the load:

Greenlight is far from perfect, and there's still some residual backlash from the flood of 'garbage' that went through before they put the entrance fee up, but it's leagues better than the old system. Getting a game on Steam is now much more possible for indie devs than it was before that program started.