http://builtwith.com - made for fun not to make money but now its profitable by a team of 1 :)
I think the idea is to not start with the thought "I want to make a web app that makes money" but "I want to make a useful web app that solves a problem" - the money will eventually come if you crack that nut!
I think the idea is to not start with the thought "I want to make a web app that makes money" but "I want to make a useful web app that solves a problem" - the money will eventually come if you crack that nut!