Blogs on WordPress.com, the hosted service by WordPress running on the multi-blog version called WordPress MU, were available via invitation only until now. But on November 21st 2005(as I noticed), the invite only barrier was lifted & it was opened for public registration!! 😀
WordPress.com is a hosted blog service like Blogger, LiveJournal, TypePad, which allows you to create a blog of your own. But this service is free & its better since its running on WordPress!! 😉 It provides you a sub-domain of your username(so choose carefully since it can’t be changed) and protects your blog from spam using the Akismet. You can find FAQs on WordPress.com at the WordPress.com FAQ Blog.
You can use Akismet on your self-hosted WordPress blog as well, its free for personal use, but you’ll need an API Key for that. And where will you get the API Key? From your WordPress.com blog!! Yes, since all blogs on WordPress.com are by default protected by Akismet, you don’t need the API Key available to you on your profile page in the admin section of your WordPress.com blog. So you can use that API Key on your self-hosted WordPress blog, but I think that one key is valid only for one WordPress blog.
One thing to take note of is that if you have not already noticed or if you are a new account holder of WordPress.com, well, you might see some changes in the admin interface now & then, don’t be surprised or alarmed, the service is developing!! 😀