I'm pretty sure every game developer has had the following conversation in the past three years.
"Dude, look how many people play WoW."
"Yeah, if we got like 5% of those people we'd outsell our best selling game."
"And be rich. We could totally buy HDTVs."
"Dude, we should totally make an MMO."
"Totally."
"Dude."
You get the idea.