- Fun. Lots of fun. This bears the fruit of knowledge too.

- Some form of "marketing" or "exposure" to the inconsequential side projects that you do and probably thought no one really cares about

- Some small amount of internet money ~$10/month enough for the site to pay for itself from AdSense

- Expert networking gigs ($100 to $200/hour). Basically, they connect you with their clients on consult about a certain topic. These are rare though. I've only done 2/7 successful arrangements so far.

I'd do it all over again in a heartbeat.