I literally just stumbled on this on accident. I was going to Robert Scoble’s hosted WP site and typed it in slightly wrong. As it happened, I was using Flock and I was recognized as such. And I was gifted a free hosted WordPress.com site. VERY COOL. Although you actually don’t have to have Flock to get it. If you’re using Firefox and have the User Agent Switcher Extension, just create a new UA with the following User Agent string:
Then go to WordPress.com and enjoy!