When you create your username in WordPress or WordPress.com, it has to be all lowercase letters (or numbers) with no spaces. That doesn’t look very professional when you username is associated with a post or a comment on your blog or someone else’s.
Fortunately, you can customize how you want your name to appear on WordPress (or WordPress.com) blogs, and the screencast below shows you how. It also shows you the process for uploading a photo (or Gravatar) to also be connected to your WordPress comments (or posts, if your WordPress theme includes Gravatars on posts.)
There are several other customization options to which I briefly allude in this screencast, but the two I’ve listed are the most important, in my opinion.
Update: You can view the screencast in the SMUG group in Facebook.