I've interacted with a several people who question the benefit of Twitter and whether or not it will last. I ran across this article entitled "Twitter Quitters Just Don't Get It." Among other things, it states what Nielsen online research found that 60% of new users leave within the first month. Here's a couple paragraphs better explaining the uses of Twitter:
"In my opinion, the most commonly heard complaints about Twitter stem from a misunderstanding of it. Chief among these complaints is the utterly bunk assertion that it's just a whole bunch of people heralding the trivial events of their daily lives into the void. (i.e., "I'm going to the bathroom now!" or "Eating a yummy ham sandwich!") Frankly, if that's how you're using Twitter, you're doing it wrong, and you should stop without subjecting your friends to a full week of that rubbish, let alone a full month.
Another prevailing myth about Twitter is that it's just an expression of our collective narcissism, and that we're all just tweeting to hear ourselves tweet. In reality, though, the overwhelming majority of users follow far more people than follow them. And if you're tweeting more than you're reading, there's a good chance nobody's following you."