I don’t get Twitter. I like their original idea of broadcasting text messages to a group of friends, but their current incarnation is to blast vapid celebrity comments to thousands of sheeple. My metric for a useful business is, “Would you buy it for a dollar?” If Pandora or GMail or Yahoo Finance forced me to cough up $1/month, I would definitely pay. When Jott removed their free plans, 30% of their customers were willing to pay $4/month (not me). If Facebook charged $1, most of their users would pay (not me). But if Twitter charged $1, how many of their 20M users would remain? I’d bet only a small percentage would pay, thus losing their critical mass. However, what if those with lots of followers (>1000) had to pay some tiered rate? If people are using Twitter to promote themselves and their products, then they should pay for that privilege. Twitter is certainly worth a dollar to someone.