I just made a username, testing the waters to start a blog, and the username I really want is unavailable. Do usernames ever expire due to inactivity, or are there ways I could find posts/comments by this person to see if they are active or not? Are there ways I could e-mail this person if there are no recent posts, asking for the name?
Usernames never expire. You could attempt to contact the owner and ask them to transfer it to you, or you could simply change your nickname and that will change the way your name is displayed everywhere other than the forums and Dashboard. Do that on your Profile page.