There is of course a middle ground between 'writing for writing' and 'writing for payback'. For instance people might want to post how they did some stuff, with the hope that it helps at least one guy. That's how most blog were written.

Then internet slowly became a place where everything is a business opportunity, and blogs were relayed into the second zone. Google also somehow became much less useful when it comes to find good blogs, probably because of aggressive SEO.