PPC Self-Cannibalization

(Part IV of a Series on Web Analytics for Search Engine Marketing)

There are lots of ways the web analysis can supplement or improve your overall Search program. Many of these take advantage of the unique cross view that web analytics provides across PPC, SEO, external advertising and direct traffic. By providing a comparative view, web analytics is ideal for finding the right balance of competing programs. Today’s installment is on PPC Self-Cannibalization – cases where a visitor re-enters a site multiple times from a Search Engine.

The classic paradigm for Search Engine Marketing acquisition is to bring new visitors to the site before or at the moment of decision. Once the visitor is on the site, the assumption is that either conversion will take place or the searcher will re-visit the site by going directly to the site next time.

Most of the time, the classic paradigm is reasonable. But it can miss a fairly significant percentage of PPC / Organic traffic – searchers who re-visit a site via the Search Engine. There are two pretty common paths for this – re-entering by the same Search Term used initially and re-entering via the company name. This second alternative can be particularly misleading.

If searchers re-enter by the same path they first used, the consequences aren’t particularly serious for measurement. The Ad Group/Search Term still gets credit for the conversion – and since you paid for multiple clicks the cost/conversion is still correct.

But many visitors re-enter by using a "brand" term. Since many PPC engines generally credit only the last keyword used for the conversion, this makes brand-terms look better than they are as acquisition tools while simultaneously degrading the apparent performance of all other categories.

Once again, this is a measurement task that most web analytics systems can do fairly easily. By tracking visitor segments over a fixed historical period, it’s quite easy to see how often multiple referrals – both from the same and different keyword sourcing actually take place. As with Organic Cannibalization, PPC Self-Cannibalization analysis can provide significant corrections against mis-optimizations or misunderstandings about the actual value of certain types of words.