I don't spam, I hate that crap too.
I do send out tons of info on emails, some of which I create my "special" tracking email to see who is serious and who is not.
Every email I send is by invitation only (they invite me) and I allows have an opt out function whereby they can be removed.
I've got over 5,000 RE contacts and have them grouped into categories that I email info too. I also mail the RE newspaper to clients that dont like computers; about 50 of them right now. When I detect a buyer getting serious about a target market, then I hone in on them personally; of which I'm currently focused on about 50 hot leads from my group of contacts.
My biggest group of clients is waterfront buyers.
FWIW