Crude attempt at trying to figure out a user's email address if Contacts access is granted. As far as I know, Square first came up with this approach (only works if their device has a default name e.g. "Bryan Irace's iPhone").

This probably isn't production ready and likely doesn't work in non-English locales.

Usage

NSString *emailAddress = [BRYEmailAddressDetective determineEmailAddress:
                          [UIDevice currentDevice].name];

License

Available for use under the MIT license: http://bryan.mit-license.org