Twitter discussion aside, this is one of the most compelling 'sales' posts I've seen in a long time.

It offers the reader something of value just for reading it, with the promise right there up front, and it introduces the product naturally as a solution to the difficulties that arise doing this by hand. The only think that seems to be missing is some kind of social proof.

Justin: great work! Can you post some feedback as to how it affects your signup rate in a week or two?