That said, I agree that your co-founder and you have to agree the product is worthwhile. I'm just saying; don't expect this enthusiasm right off the bat; that is really only going to happen if your technical co-founder has never listened to a well-pitched bullshit idea.
PS: I run a site dedicated to finding co-founders: http://fairsoftware.net. So I have some experience in the topic. Share your idea: don't be scared that someone will steal it from you. Most people will think your idea is bad anyway. Your job, as the business founder, is to convince me, the technical guy, that you can make it happen. Do you have customers lined-up? Can you raise funding?
If all of these align, then get to know each other, work for a month on the idea and see how you feel then. Then formally commit.
Has to believe in your idea? For me this is a warning sign. It could be the result of the other party being dominated or submissive. I'd much prefer a committed co-founder who is flexible and can be swayed by merit at the same time be critical where necessary.
The list also reminds me of a "what to look for in an employee" article.