I think it would be better to have the mobile number as another way of logging in the website.

People generally have the mobile numbers handy, as compared to email ids, which we generally don't have, for acquaintances, or friends.

Plus, it would be easier to invite, share, etc. Good for adoption, I think.

Very cool! Thanks for making this - every week I hear someone mention that they want to stop using Facebook or Google products. (Too invasive.) How do you see this being different than Eventbrite?