Captain Beefheart is right. Everytime I see a guy who gaily writes his E-mail on a public board, I think
"Huh, probably you don't know what Viagra or penis enlargement treatments are, but you're going to!"
Anyway, prevention is sort of a wasted time when your contacts know nothing about spam. Just one massive mail containing that silly Powerpoint joke, sent to thousands of contacts written in the "TO:" field, is a treasure to spam collectors.
Please: every time you have to send something to multiple recibients, use the "BCC:" field to write them. Just include a bogus E-mail in the "TO:" field (like
bill@gat.es) and everything'll be OK.
P.S: I hope
bill@gat.es doesn't exist :P