I started using Twitter about a year ago and am sort of surprised at how much it's taken off. I don't use it as much as some, but I enjoy reading what others are doing.
I recently read a humorous article in the July/August 2009 issue of More Magazine called "How Not to Act Old". The author, Pamela Satran, has written a book with that title and also has a blog. If you click here, you can read her blog about how not to act old on Twitter.