Does what it says on the tin, really. Visiting old derelict buildings and letting others see. I've just been introduced to this website which does just that and there are a few places in and around Aberdeen. Some quality photos, some pretty creepy too, especially those from asylums...
UK Urban Exploration Forums
There's Satrosphere
Satrosphere Aberdeen 9/3/08 - REPORT - UK Urban Exploration Forums
and although not exactly derelict, the Bon Accord Baths
Bon Accord Baths, Aberdeen, 30/01/08 - REPORT - UK Urban Exploration Forums
For anyone who hasn't seen these yet, there's some impressive viewing!