- Casual geeks. People who want to know what we know, but just don't have the time + know geeky tricks.
- Urban demographic. It's valuable and something overlooked in the tech space. Why do you think all of those things trend on twitter with weird hashtags? It's because of the urban demographic.
- Family living. People want tips for better family living. It's also a valuable demographic.
- College focused. Do .edu email addresses only and segment by city. This is how facebook got started and college humor spread. It's highly viral and highly valuable. Think financial companies paying for a dedicated email to 100k college kids with good editorial content.
- Male fitness. Sort of mens health meets GQ. Fashion, sex, fitness,money,etc. Women often get all the love here when it comes to content online, but this is a gaping hole. If you've ever picked up a fitness magazine, you would know advertisers spend a ton here.
I think there's more. I'd start with either the first one or last one. If you end up doing one of those, I'd love to help in some way possible.