I'd guess that their work on Wufoo was taking up all of their time. They solved the payment challenge, except it was a front-end solution for customers, not dev

I'd guess that their work on Wufoo was taking up all of their time. They solved the payment challenge, except it was a front-end solution for customers, not developers. Might have been a larger market to go after. I don't know how much Chargify makes, but Rusenko had to build Weebly's payment system and he didn't like doing that. Same story with Djangy. WePay also comes to mind, but I don't recall them seeming frustrated about implementing theirs. I would imagine it's such a difficult problem (or would have been in 2006) that it'd feel like running another full-time startup when they still had the challenge of delivering a good form builder as their main priority.