This is something I’ve been working hard on with my co-workers on the Diaspora project. We’re moving towards helping the community of our users and developers make decisions on the project’s direction, after two years of development.
Someone shouted “Tumblr!” when I was at Wal-Mart. I gasped, and then I looked to my left. Seeing nothing, I looked to my right. Whoever said it knew automatically that I’m a Tumblr user. Go try it out in Public at random. Only then will you find truth.