Those are the reasons I blog, and probably why 99% of all blogs were started.

In olden days (five years ago), blogs were "open" and social networks were "closed."

Blogs let you put your ideas out on the wild, untamed Internet for all to see. Social networks, on the other hand, were "walled gardens." Blog posts were public; social networks were private.

In the past year, that situation has essentially reversed, although many bloggers haven't realized it.

The social networks have knocked down the garden walls, encouraging public posts accessible to anyone, even if they're not "friends" and even if they're not members of the social network.