Anti-spam advocates argue that spamming is unethical and that it robs users and Internet service providers of valuable computing resources. Whether you agree with this ethical argument or not, you'll have to agree that spamming is a risky proposition.

Spamming is widely hated among Internet users, and those who hate the practice can do real harm to your business. Getting labeled as a spammer can do much more than subject you to a deluge of unpleasant flame mail.

Some Net users are capable of technological retaliation, such as sending e-mail bombs -- large e-mail messages that can clog or even shut down an e-mail server. One company naively hired a bulk e-mailer to send out an ad for them. The company received thousands of complaints. Someone set up a robot that called their toll-free number over and over for three days.

Spamming can also get you in trouble with your ISP. Most service providers prohibit unsolicited commercial e-mail on their systems and will shut down your account -- or even remove your Web site -- if they find out you've been involved in the practice.

As an email marketing consultant, I recommend that online marketers seek out low-risk methods for using email. I've formulated an Email Marketing Hierarchy of Risk, which lays out email marketing methods in a spectrum from highest-risk to lowest-risk, like so:

Highest Risk

Rented spam list
Homemade spam list
Targeted spam list
One-time unsolicited invitation
One-to-one cold canvass
Rented opt-in list
In-house opt-in list

Lowest Risk

The highest risk comes from engaging the services of a bulk e-mail company, which will send your ad out to a blind list of recipients, many of whom will object to receiving your message. Building your own spam list or a so-called "targeted" list are also high-risk activities. Somewhat less risky is sending out a one-time invitation for people to join a standing list. And a personal message sent one at a time to a carefully vetted group of recipients might not be unwelcome -- if the message is carefully crafted, short and tactful.

Least risky on my hierarchy is the opt-in list, whether "rented" or developed in-house. This is a list of recipients who have actively requested to be on a list. Opt-in recipients will welcome e-mail from you, as long as it is relevant to their needs, and as long as you don't mail so often it becomes an annoyance.