ImpressionRank is the number of times users viewed the page, while browsing search results returned by the search engine. In turn, ImpressionRank has an intuitive correlation with power law search query distribution.
Estimating the ImpressionRank of Web Pages proposes a number of methodologies for estimating ImpressionRank. It is based on sampling of search suggestion services provided by search engines and on extraction of popular keywords extracted by web pages. The paper achieves quite interesting results in terms of recall and convergence speed.
I am pretty sure that the work is quite interesting for all the SEO companies.