> When I started my career I spent a fair bit of time answering questions on Stack Overflow rather than asking questions.

I don't think you can answer SO questions as a hobby any more. I used to do it on my morning coffee but at some point it got full of professional reputation growers that answered everything 30 seconds before it got posted. And when you do find an unanswered question the mods jump on you for giving "teach the man how to fish" answers instead of ready to copy/paste code.