Medium danger
How high is your junk-mail tolerance? If you can bear a few messages each week, these online activities probably won't cause you too much anguish. In each of these situations, a little caution saves you from a lot of unwanted mail.

The culprit: registering a new domain

Spam servings: nothing for months on end, then occasional outbursts
I registered several domains with Register.com using a dedicated e-mail address created especially for the purpose for the administrator and billing contact fields. This is public information. Anyone can find it by searching Better-Whois, which is often used by Web hosting companies for bulk paper mailing. But on the e-mail front, months went by with nothing but administrative messages from the domain registrar. If you have the same experience I did, you'll see an occasional query from someone who wants to buy your domain. Otherwise, zip.

But just wait until it's time to renew your domain. Competing domain registrars (including Network Solutions) began sending me monthly e-mail counting down to my domain's expiration date and trying to get me to switch. This is not random bulk mail but highly targeted marketing from businesses that knew exactly what I was up to. They had apparently mined the domain registry for pertinent data, possibly with help from Network Solutions.

The remedy
How can you avoid precisely targeted unwanted mail? Reply to it. Put remove or unsubscribe in the subject header, or follow any instructions within the actual messages. Most real business e-mail provides a functioning remove link. If the message comes via paper mail or phone, contact the company with a request to stop. Any business that's savvy enough to cross-reference records with a domain registry is smart enough to stop if it's about to lose a customer (we hope).

The culprit: e-mail links on my own Web site

Spam servings: nothing for months, then a steady stream
Ah, the siren song of Web mastering: your name in lights, your own e-mail account that begins with webmaster@, your words available to anyone in the world! In my experience, the appeal is hugely overrated, and here's why. I published one of my virgin e-mail addresses on the pages of my well-trafficked domain and another address at some freebie sites at Tripod and GeoCities.

Once in a while, someone would offer to drive my Web counter ballistic with a search-engine secret discovered by a computer-illiterate man in Massachusetts. (This is actual spam, people.) No big deal. But as time wore on, the spam ran thicker, mounting to four or five items on some days. The addresses had clearly gotten onto a list somewhere, but it wasn't peddled as widely as my highest-risk forum posting.

So, what's left? Show me which activities serve up little or no spam