The second of most common direct marketing measurements is cost per piece. To find cost per piece, you would take total cost of mailing and divide it by total number of pieces sent. For example, if total cost of mailing was $4,500 and you sent 2000 direct mail pieces, cost per piece would be $2.25. This is an important figure to keep in mind, because by lowering cost per piece (as long as number of responses stays same), you can lower cost per acquisition.

The third of most common direct marketing measurements is response rate. The response rate can be calculated by taking number of people that responded and dividing it by number of people that were sent direct mail package. For example, if 2000 people were mailed a direct mail package and 20 people responded, response rate would be 1%. This is an important tool that you can utilize to forecast success of future mailings.

By using all three of these common direct marketing measurements, you can finally determine which half of your marketing is working, and which half is not.

How Can You Deter It?

Many advertisers know about possibility of click fraud but generally haven't done much in past to prevent it. Some feel that if they complain to any of search conglomerates, it could ruin their free listings. Others feel like problem is beyond them.

"It is a bigger problem, but folks just don't want to take time to track it down because it's a complex problem," stated John Squire, of web analytics firm Coremetrics, to CNET. "Given that some of largest marketers manage up to 1 million keywords in a campaign data can be difficult to crunch."

Companies who do understand and report click fraud to search engine properties have had success receiving refunds for fraudulent clicks. For those advertisers who want to address possibility of click fraud in PPC campaigns, good option do exists. At most basic level, advertisers can use general auditing; many have been known to compile lists of sites that generate high numbers of clicks but not sales. This will indeed put up a red flag.

On other hand, because click fraud is advancing at such frequency, click fraud detection companies and software have been popping up all over country. Let's take a look at some of options:

ClickDetective - ClickDetective allows you to track return visitors to your site and alerts you if there is evidence that your site may be under attack. Its reports show you every click in real time rather than a summary hours later.

Who'sClickingWho.com - This fraud detector tracks all PPC search engines, detects multiple IP's, and even pops up a "ClickMinder" after a potential abuser clicks repeatedly over five times.

BogusClick - BogusClick can help advertisers determine competitor IP addresses, originating PPC search engines and/or partner sites involved, as well as keywords used.

Clicklab - Clicklab employs a score-based click fraud detection system that applies a series of tests to each visitor session and assigns scores. Calculations are made to indicate bad/good sessions to show an advertiser quality of traffic.

Click fraud is a big problem in search engine marketing that's only going to get bigger in future. It is wise for any online advertiser to implement some auditing system. Why continue to waste precious campaign money?!