A tweetwhore is like a 'postwhore', but only on Twitter.
1. Tweetwhore, or "tweet whore" is a term used on Twitter to describe a person who measures seniority by one's numerical tweet count.
2. The act of 'tweeting' large amounts of meaningless tweets on Twitter.
3. One who floods the Twitter updates with tweets in order to gain a higher tweet count.
Karen is such a tweetwhore, she sent 500 tweets on Twitter in only ONE HOUR.