Where does the time you spend on Stack Overflow come from?
My number 1: My projects take a couple of minutes to compile and run, so that gives me the time to help people or find some answers (or to learn something by browsing interesting questions).
Some other answers I can imagine (which don't apply to me):
- Getting paid by the hour and you just charge your client.
- Favorite spare time activity.
- Being a n00b to programming, you don't have a choice but to visit (Stack Overflow is the best).