Dave Copeland is a programmer, and he speaks a lot of truth in his recent blog post:
Google+ isn’t about sharing cat pictures, it’s about serving ads. Twitter’s massive network of 140-character bits of information isn’t about connecting people across the globe or to view current trends in worldwide thinking, it’s about serving ads. Facebook isn’t about entertaining yourself with games or sharing interesting links, it’s about serving ads.
There’s nothing wrong with serving ads – but there’s one big take-away: do what you love and the rest will come easily.