Here's a wacky idea sure to attract the attention of your top prospects - send them a fake hand grenade!

One assumes this was the thinking behind a campaign dreamed up by an L.A. law firm and their Silicon Valley marketing consultant, who last month mailed 100 packages containing plastic replicas of hand grenades to executives at top Northern California companies (tag line: "we go to war for our clients"). It's unknown how many leads the campaign generated, but it did prompt several calls to the bomb squad, a building evacuation, complaints to the postal authorities and an investigation by the U.S. Attorney's office.

Dimensional mailers are all the rage. Creative directors love them. Award competitions sing their praises. But do they work?

If you judge by response rate only, the answer is a qualified yes. A well-crafted, eye-catching dimensional mailer can often draw response rates of 25 or 50 percent and higher. Where dimensional mailers fall flat (if you'll pardon the pun) is on two counts - cost and lead quality.

A response rate can be anything you want it to be if cost is no object. (Need 100 percent response? Just offer a free Mercedes to anyone that responds to your campaign.) Dimensional mailers generate phenomenal response, but usually at a staggeringly high cost per lead. If your target audience is all of 100 executives, and you're not so interested in cost per lead as much as achieving the highest possible penetration of that finite audience, then a 3-D mailer is for you. Otherwise, you can almost certainly develop leads at a much lower cost through more traditional (albeit, less interesting) means.

Secondly, what kind of leads are you really generating? Most dimensionals aren't really direct marketing campaigns at all; they're just bribes dressed up in a fancy package. If an executive agrees to meet with you because you sent him or her a Callaway driver, is that person expressing a genuine interest in your product? Or are you just buying that person's time in the hope that her company will be a fit for your solution?

Before you embark on a dimensional campaign, ask yourself these questions:

1. Is my goal maximum response at any price, or is it minimum cost per lead?
2. How much is a lead really worth to our company?
3. What qualifies a prospect as being a genuine lead, and will this campaign generate those kinds of prospects?
4. Is what we're sending the prospect likely to evacuate his or her building?