I'm curious what the monetization strategy is for these types of social news sites (ex. Newsley, Rubyflow, markenomics, etc., etc.). Or is the motivation to do the work to build this type of site (both structurally and in a community sense) born out of strong interest in the subject and perhaps the chance of potential indirect future rewards (networking, jobs, etc.).

I ask because I'm interested in a couple of other subject areas and considering building a similar style of site and thus wondering what realistic expectations should be re. the potential for direct monetization.