What probably prevents you, as an ethical and upstanding e-business owner, from sending spam is that you are probably on the receiving end too. Like most Internet users, you are inundated with unwanted e-mail, making you very respectful of the concept of "opt-in."
While there hasn't been an entirely foolproof method for eliminating the uninvited mail, here are some suggestions for reducing the amount:
Don't respond or opt-out to any unsolicited e-mail you receive. Doing so qualifies your address as "live" where it will wind up on a multitude of other lists.
Set up filters for incoming mail; most e-mail clients and services are helping to fight the battle. Microsoft Outlook uses a comprehensive customizable rules system to distribute mail to your folders and trash. Yahoo! mail immediately sorts bulk mail into a separate folder and also has a "block sender" feature.
When posting to message boards, newsgroups or other public forums, add an extra component to your e-mail address so it hinders the spambots. For example, change JohnSmith@abc.com to JohnSmith@abc.complete. Those who want to respond to your post must manually type your e-mail address or remove the extra component.
Establish multiple e-mail accounts, each with a separate purpose. Use one for corresponding with family, friends and another for business associates; create a separate account for e-commerce orders and opt-in newsletters; have another for newsgroup postings. Don't get too attached to any of them since you might have to abandon it if the spambots catch you.
If spam becomes a debilitating nuisance, you may want to use a professional filtering service. Yahoo! identifies more than 26,000 matches on "spam filtering" and ECommerce Guide's Product Finder lists 283 e-mail tools, including filtering systems. Here are articles on two popular services: Spam: Time for a Better Tech Solution and Your E-mail Bodyguard
Don't get mad, just delete! Resign yourself to the inevitability of spam, just as you deal with the countless junk mail and uninvited catalogs that you get via regular postal mail.
Finally, report junk mail senders to your ISP and their ISP.