I got a mail from Oxfam sayng "Go here and sign this!" which I dutifully did. But the form has a feature where you fill in your postcode, and then there comes a clicking and whirring and then you get a pull-down list of the addresses covered by that postcode. 10, in my case (I'd always heard 6 as the magic number).
A) Cool! B) Is this legal? I can't think of a good reason why not, but it does seem to be edging close to Reverse Phonebook territory.