SPAM is unsolicited bulk email. If the recipient has not verifiable granted deliberate, explicit, and still-revocable permission for it to be sent -- it's SPAM. Just because the user once bought something from you doesn't mean that they'll be happy that you're going to send them email for the rest of their lives. However, it also doesn't mean that they DON'T want you to send them email. Therein is the conundrum. So take your customer list and send them an opt-in email asking if they want to continue receiving promotions & information from you. Those who reply are one your real non-spam list. Make sure they always have a way to unsubscribe and then you're not sending SPAM.

To me it is like "nails on a chalkboard" when many people talk about "sending out spam" to their friends, neighbors and customers. What they mean is an e-mail blast to a list of people who have something in common (family, membership, etc.), not spam.

Spam is totally unsolicited and the e-mail addresses are usually obtained by trolling through the Internet for addresses sitting innocently on web sites -- on company or school directories, for example. For this reason, many universities have put some "guards up" on their published e-mail addresses so they cannot be cut and pasted directly.