Hi Janie,
A good point well raised.
The easiest way to enable this feature is to login, hover your mouse curser over PROFILE from the top menu and then Summary> Modify Profile> Notifications. This will then allow you to set the global options for being notified of any posts etc.
It is not possible for an admin to do this by default as not everyone would like this feature, especially (as you point out) if the traffic increases.
You can also do it for individual threads each time you post or reply using the tick boxes under the message window (Notify me of replies), thereby making it more selective.
Thanks for advertising us in the US, and if you have any other ideas on how to promulgate the site in a better way then don't hesitate to get in contact!!
Regards,
Duncan