If you want to keep a tab on updates from WordPress you must have an account on
wordpress.com. Automatticans test the code on the biggest installation of WordPress MU, the wp.com! they activate the nightly builds and RC's {release candidates} on
wordpress.com! having an account on
wordpress.com or
wp.com means you can use Akismet too on your self hosted blog but for personal non commercial use {for which you have to buy a licence} Akismet key can be used for Akismet and wp-stats plugins plus if you have an account on wp.com you can use
jetpack.me's powerful features! having a blog on WordPress.com means you have the cloud power of
wordpress.com servers {with a few limitations} uptime of which is around 99.9% beatable only by Blogger so you can always use it as your main blog or status blog as twitter does by hosting a blog on tumblr but Blogger and wp.com are recommended for status blogs, because even tumblr and posterous had a major outage tumblr was down for a day or two and posterous were busy shifting their servers!
