1. The account signup should check for multiple emails. Currently it doesn't.
2. Can a user who already has an account able to connect his Facebook/Google/Yahoo/etc account with it? Forexample, if I already have an account and one day I decide to use facebook to login, can it give me two options: a) continue creating new account or b) login with previous account and the system merges them together?
3. Notification emails. I know you are not done but when will these be implemented?