VideoBit email notifications

A user will get an email every time when:

1. They create a new Topic
2. Someone replied to their Topic
3. Someone commented on their Reply
4. Someone commented on a Reply where the user has also previously recorded a Comment
5. Someone shared a Topic link with the user via email

Additionally, a non-user can receive emails from VideoBit if:

1. Someone invited them to create a VideoBit account
2. Someone marked the non-user as a legal guardian of an underage user