I would make one targeted at women, maybe of specific age groups. Women make up over 50% of the internet use now and in my opinion seem not to be represented

I would make one targeted at women, maybe of specific age groups. Women make up over 50% of the internet use now and in my opinion seem not to be represented well on digg/reddit or many of their clones. With django its easy to setup multiple sites, you could run several instances of the app to target different niche users and see which ones stick.