The inspiration for the survey came from the numbers we were seeing on our site (across 10's of thousands of signups). There was a clear preference for signing

The inspiration for the survey came from the numbers we were seeing on our site (across 10's of thousands of signups). There was a clear preference for signing up with email vs facebook. The in person survey is too small to provide meaningful numbers, but it was useful to hear real people's feedback and sentiment. I agree that it seems weird that people would rather give their email than facebook because they "don't want spam". But that's really what they said, so that's not speculation about their reasons. And again, the survey was asking people about their experience and feelings about sites they've signed up for, not just about our site.