I guess most people don't help on Stack Overflow expecting any financial reward (maybe reputation) as the vast majority are already working. And, at leas to me,

I guess most people don't help on Stack Overflow expecting any financial reward (maybe reputation) as the vast majority are already working. And, at leas to me, it's more of the spirit: "Help others, and others will help you" (you also learn a lot by answering questions and having comments on them).