"We had to spend two months writing the whole billing system up; Chargify and those services didn’t exist at that point. So, if we wanted to have recurrent billing we had to write it ourselves and do all the logic"
If you implement a new service out of necessity to solve a problem you have at work, it is a very good indication that service is also needed by other companies. Instead of using this service you created internally only, you should release it and see if there is a great demand for it.
I think this was a missed opportunity for Wufoo to create another great service.
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.
If you implement a new service out of necessity to solve a problem you have at work, it is a very good indication that service is also needed by other companies. Instead of using this service you created internally only, you should release it and see if there is a great demand for it.
I think this was a missed opportunity for Wufoo to create another great service.