Every programmer sees message boards and quickly runs down a database schema for users, comments, and upvotes, because they're all trivial and almost identical. The user base that builds up is the value. In the case of Reddit, I don't mean to imply positive value, but that's the value.
Endless injection of cash? Sometimes I think that the VC model is wrong, and taking a few pages from bootstrapped start-ups might make lot more sense...
