yes great feature to have but make sure the user can enable or disable it in there profile or something as i dont want annoyed users emailing me to stop them getting spammed by comment notifactions.

maybe an option in there profile to globally enable or disable emails from comments and also an option when uploading a video and edting it to "email me when someone comments on my video" Yes or No.....that way they could only get emails from comments on some videos rather than all or none if that is what they wanted.

also what about an email if someone sends them a private message?...again with option to turn off or on.

These emails need to be editiable inthe email templates section...i notice the new "email users when there vids are added to the site" option is not editable.