[chunky1994]

I would say that the reason people tend to look for developers who work on side projects etc. tend to generally be good developers, while those who don't can go either way.

It's hard to know whether a developer is good or bad with only a resume/interview. If you're looking for smart motivated people, the ones who tend to work on side projects etc. can actually show you stuff they've built, and generally you can get a good idea as to how/if they'd fit in with your company/start-up.

While this doesn't mean developers who don't take on side projects are bad, it's just hard to identify whether they are in fact good or bad.