On the Web: Want to Increase Your Online Sales?

The Second Step: Allocation
Next, allocate sales to each traffic source. Here's where reporting gets tricky. The problem is that the tracking and reporting software for different types of web traffic over-report associated sales. It's very good at reporting costs, but terrible at reporting sales!

Google AdWords, for example, places a cookie when someone clicks through an AdWords link. If a consumer doesn't purchase on that click, but later comes back via an email and purchases, Google gives the AdWords click credit for the sale. Of course, your email program will give the email credit for the sale as well! The result is double counting of sales.