At the moment there are 2 places that record you as having joined an area. One on the old website which manages the emailing to you from the area rep and one on the new website that shows events, etc. in your profile for the areas you have joined. There is an onging project to move the "email area members" function to the new website so that "joining" an area has more functionality. We'll announce the changes properly once they are ready. Shaun