[pbiggar]

I agree with all of this (caveat, downplay the "interviewing" angle a bit), and let me add some more things I found helpful in my recent cofounder search:

- the most important thing for an early stage startup is that they can validate. That means building incomplete and imperfect prototypes quickly and repeatedly. "Getting the architecture right", "clean code", etc, are usually the wrong skills for a super-early-stage startup, and your CTO shouldn't prioritize them.

- more important is that you get on well with the cofounder. You're going to be working together for a long time. Make sure your personalities mesh, that you can spend a large amount of time together, and that you can discuss/argue constructively.

- Having the same values and goals for the company are paramount. When finding a cofounder recently, I wrote a questionnaire with 40 open-ended "values" questions for cofounders to answer (and then I sent them my answers). It was very apparent when I met someone with values overlap and when I didn't.

Ended up with a great cofounder, have been working together for 6 months now: http://ellenandpaulsnewstartup.com