How does opt-in differ from unsolicited bulk email (spam)?
Bulk emailing (which is commonly referred to as “spam” or “spamming”) is the practice of transmitting mass quantities of e-mail to large lists of “unqualified” email addresses. These lists are harvested without the recipients’ knowledge or consent from newsgroups, chat rooms, Web sites, and member directories. Therefore, these lists are generally less expensive than opt-in lists.
