I also received an email, do not have an account, even a partially created one like you. Odd.

I knew I had an account but it was via oauth and I had to create a "real" quora account in order to delete it. The notice that they were storing contacts from other social networks was the part that pushed me over the top towards deletion.

This must have been it. Still not sure at which point I've ever logged in to quora, but I can't think of any other explanation