Jeff has written up a great post about the history of WordPress.com and includes screenshots from the last while, and it makes for a fun tour down memory lane for me as I have been a WordPress fan since long before the WordPress.com site was developed to become what it is today.
WordPress.com has been around for a long time, long before I even knew there was a WordPress. Upon browsing through the results that the internet archive has, itís very interesting to see the progression of the site/service. At one point, it looks like Matt or Automattic lost control of the WordPress.com domain but eventually got it back. Also worthy of note are the links to OpenDomain.org which was a service that provided opensource project domains. I have no idea if WordPress was an open domain or not but it certainly appears as though Drupal.com was.
I highly suggest checking out WP Tavern to read the full post.