We did actually consider prompting for an email address once they sign up with Twitter. However, whenever I've used an app that does that to me I just leave the

We did actually consider prompting for an email address once they sign up with Twitter. However, whenever I've used an app that does that to me I just leave the site and don't go back and thought that if I didn't like it happening to me, it wouldn't be fair to do it to others.