If your revenue comes from ads, then almost by definition, small community == small revenue.
Imho, leveraging pg's experience in start-ups and the community here seems like a better way of exploring monetization options.
Look at it this way: of the following ways of monetizing, one could argue that the more niche-specific, the more potential the model has:
- ads (target: just about everyone)
- sell a book/magazine about running a startup (target: people interested in start-ups)
- fund start-ups that came about partially thanks to HN (target: people doing start-ups)