Believe me, I was skeptical too. I remember sitting in a car driving back up from YC with Michael Siebel asking him: "Hey man, do you think I am absolutely nuts thinking people would pay for a browser that's FREE? That's an idiotic idea right?" and, of course, he encouraged me and I am still feeling pretty encouraged based on talking to users and seeing the revenue/usage/praise 18 mo later.
We have a lot of work to do and I am pretty embarrassed of what we've got still but it felt right to get public about it.