Emails should be taken from Login API and notification should be enabled by default.

[powerriegel]

When I log in via Facebook there seems to be no email stored in letsmeet. Unexperienced users log in, think everything is done and leave the page. They will never come back as they receive no email.

Other sites using e.g. the Facebook Log-in can take the email from Facebook. This should be done automatically. For example Stackoverflow.

Notifications should also be enabled by default.

Otherwise you need to tell any user to log in, add an email, enable notifications. Thats annoying.