When you have many users who all login at different times and they need to get a message to you(admin/owner).At the moment they are using the chat line to leave those private messages visible for for everyone else to read(before i can login and remove from chat line). I would have liked to see a new feature called "PM Admin" or similar that will allow users to leave a private message for the admin, then when i login next time, i see " x new messages available" just like here in the forums and i can go through them. If this can be extended to all users it will be a huge bonus.
If the handling, storing & management of the messages is too much for SS, then as a cheap solution, i would at least want an email to be sent to my pre-defined email address whenever someone sends me a PM(not all my users have my email) and i don't have their's either.