ASK THE EXPERTS: THE ART OF E-MAIL MARKETING.

Sometimes it takes just a simple example to suggest how profoundly e- mail has begun to transform technology marketing. Here's a note we got a few weeks ago from an old friend, Delahaye Group president Katie Paine: "We just ran our annual benchmarking conference and got just about everyone to sign up via e-mail," Paine told us. "We later sent out 8,000 copies of a printed brochure and probably only added another two or three attendees."

Of course, results like these are certainly not universal, and may never be. But clearly a few companies have reached (and passed) the magic cross-over point, where e-mail produces more sales dollars and more brand loyalty than virtually any other kind of print or broadcast medium. And it hasn't escaped anyone's attention that e-mail campaigns are dirt-cheap to execute and produce results almost literally overnight. Marketers have good reason to jump on the e-mail bandwagon these days.

Is there a catch? Well, yes. E-mail marketing is still a brand-new discipline whose rules are in flux. Copywriting formulas that work flawlessly in print often fizzle in the world of e-mail; customers who don't mind a mailbox chock full of catalogs and direct-mail letters go ballistic when spam shows up in their e-mail in-boxes. Does formatted HTML produce better results than straight ASCII text? How many words should be in the ideal sales letter? Do we lose (or gain) sales by asking prospects to click over to a Web page?

In fact, we're still guessing about questions like these. But e-mail marketing isn't entirely a black art: Over the past few years, marketers have uncovered a wealth of clues about what works and doesn't work. We recently polled Soft-letter subscribers about what they've learned, and here's what they told us: