The usually (very) helpful AC does seem to have rather missed the main point of your post.
However the essential element of it holds true. The only reliable way to avoid spam (irrespective of the source) is to use 'disposable' email addresses. i.e. you should have one or two email addresses which you only reveal to trusted friends and family members. (Those addresses should ideally be ones which can't be 'guessed' at by a spammer's computer system. e.g. '
[email protected]' is 'guessable', whereas '
[email protected]' isn't).
You should then create additional 'disposable' addresses, for signing up to services like the Answerbank or for internet purchases. (GMail and Gawab are frequently recommended on AB for additional, free mail addresses). Anyone who uses their 'main' email address for such purposes is simply asking for trouble. (I've used well over 200 email addresses. Only 6 are currently active but I couldn't care less if most of them started getting spammed. I'd just ditch those addresses and create some new ones).
It's several years since I signed up for AB (and things may have changed) but I seem to remember that, unless you click to opt out, you automatically agree to receiving messages from Crystal Guides (who run both UK Net Guide and the Answerbank).
To opt out of such advertising, try contacting the AB editor (using the 'Contact Us' link at the foot of this page) or emailing UK Net Guide directly, using this form:
http://www.uknetguide.co.uk/Info/EmailUs.asp
Unlike 'real' spammers, Crystal Guides is a reputable company, so there's a reasonable chance that they'll take some action.
Chris