someone with a tweeting addiction. Tweetoholics are often in denial and need tweetrehab or a 12 step program like Tweetoholics Anonymous to overcome the addiction.
A hardo is a person who tries extremely hard at everything. Most times a hardo will try very hard at things that do not require excessive effort. For example, sports practices, gym class, etc.
Wow did you see Jack at practice today? What a hardo!