Perhaps the idea is to post an idea and then get the OOC and IC moving at a rate that makes sense. I'm not interested in getting excited about something and then have a GM wait 3-4 days to post an OOC, though 10 of us jumped on the interest check the first day he/she posted it. 

Then the IC comes out weeks later. That makes no sense to me. 

Also - if you're going to throw out a story and you don't have a plot - get a creative co-GM that can help you spin one quickly because most people come to your story expecting you to have some plot points to throw at them or some direction for the game. If there is no vision or focus for the game - it will die. 

There are a million reasons these die, but some of the best ideas I've seen never even get off the ground - tragedy.