I say they're mine. As I went to research [i.e. Google: "avoiding it in the first place +SPAM" ] the rules, it seems they're pretty much the same everywhere.
- Use a "straw man" email alias in public. Sometimes called throwaway or disposable email addresses, when you get on the spammer's list you can simply change addresses.
- Read the check-boxes on the web form -- Carefully! Sometimes you have to check them to opt-out; sometimes checking them subscribes you to a promotional mailing list.
- Don't publish clear text email addresses on-line. This includes your corporate web site (encrypt the address using JavaScript or use a CGI form submission) and any forums you may participate in. The reason for this rule is that spammers use programs called harvesters to read web pages and "harvest" email addresses.
There are a couple other more general thoughts I have about how spammers get email addresses. I have always suspected that when my Aunt Millie (fictitious Aunt Millie) wrote to everyone in in her address book (and then the inevitable days of "reply to all" chatter) that somehow the adresses leaked out. A little common netiquette on the part of Aunt Millie could have prevented that exposure to SPAM.
I think in order to begin solve the problem, we must also accept responsibility to our friends and business associates who trust us with their address.
I also think the days when this can be addressed without filtering software are gone. Somewhere in your business, your mail should probably get filtered for SPAM in order to protect your workers productivity. Whether this happens at the ISP, or on your corporate mail servers is partly a matter of resources, and partly a matter how your company uses email. If you have a very small office, or your company has no systems administrators, you may actually run the anti-SPAM software on the user's workstations.
I forgot to specifically mention using BCC when sending to a list of recipients. (If you went to the On-line Netiquette site, http://www.onlinenetiquette.com/ , then you already read about this.)