I really don't see anyone but the power users being willing to pay. What's that TAM then? There are only around 250k verified users, you can probably use them a

I really don't see anyone but the power users being willing to pay. What's that TAM then? There are only around 250k verified users, you can probably use them as a proxy for power users, your pro customers. That doesn't seem very large. Though this only really would be counting power writers, not necessarily folks who consume but don't tweet.