If you are buying traffic from different sources, there is a high probability that different suppliers will sell you the same impression/click from the same user during the same session, often resulting that you end up paying multiple times for that same impression/click which in the aggregate, often ends up to be a significant amount of money saved at the end of the month.
In order to prevent this, the WD team has developed a tool called Overlapping.

Traffic overlapping tool

This tool clearly demonstrates traffic overlapping from different sources.
On the left, there is a list of information, how much traffic of the source is overlapped with other sources.
On the right (after choosing the traffic source on the left), the information is shown, which sources and how much overlap with the source you chose on the left. The figures differ on the left and on the right.
On the left, there is information grouped all over the campaign/site, on the right – there are only overlappings for the particular source you’ve chosen.

Traffic overlapping tool

The Visitors column indicates the percentage of this source to all the campaign’s visitors, and the Overlapping column shows the percentage of the source’s overlap (on the left – in all traffic, and on the right – in the source chosen on the left).
Using this Overlapping tool, you can download the Overlapping report send it back to your publishers and then deduct the % of their traffic which was overlapped from their earnings, thereby saving your advertising budgets and being an effective traffic provider for your customers.