The recipe for being a "good" bulk mailer is simple -- never send any bulk mail to people who didn't explicitly ask for it. But then, that's what you're already doing. (I'd also add a specific question on wherer a person wants to receive e-mail on your product registration form, if you don't have it there already). (A usual pitfall is not providing a user with an easy way to unsubscibe, and catching invalid addresses -- but modern mailing-list software handles that just fine). Provide a registration form at your Web site. Make Web site interesting and informative. People will come (my company's website already logged over 50k hits, though there were no any other advertisements or PR activity). Good luck! --vadim