I have recently been discussing with a client the causes and effects of a double listing in Google. This is where two results are grouped together on a search engine result page, one indented below the other.

What happens when the two pages get on to the same search engine result page (SERP) is that they lock together. If the two listings are not on the same page you can get an interesting week on week effect where one listing goes down and the other goes up by the same amount. This is the “elastic band effect” and can be the result of keyword cannibalization.

 Search Engine Land’s 100% Organic column has a good method of deconstructing what the “actual” position of the second result should be, using the &num=X extension to your Google query string. Andy Beard has some information on his site about how interlinking between posts helps to get an indented Google result (beware of video starting playing if you have sound!). His results are mostly blog posts, which means there is a natural amount of interlinking going on, and on more competitve terms it is not quite so simple!

Ultimately, as an SEO agency, we need to make sure that the work we are doing on one page is not cannibalising the results of another, so it is important to be aware of these second listings and which web page ranks. As Andy points out, internal linking is a proven way to improve the results for these kind of terms. Likewise off-page optimisation needs to be applied to whichever is the most appropriate page. In the case of my client, an indented double listing would be a fantastic result, especially for this high traffic term, but we need to be aware that both pages need to be promoted to avoid the higher ranking suffering as a result.