[ArekDymalski]

While I totally agree that you'll need to incentivize the potential users to use your app, I think that right now you've subconsciously taken the right path. To attract the users you need sufficient number of interesting ideas to show to them. That's why targeting the entrepreneurs,developers and designers (as someone brilliantly suggested) is a way to go for now imho. After that you can focus on implementing changes aimed at acquiring "normal" users. And that can be a real challenge. The perks/benefits seem to be already proven solution. I also thought about turning the "upboats" into some kind of game of prediction - can the user guess which idea will take off? Something like here: http://www.upboat.us/idea/c4861c9bf49ce663 ;)