In this video interview, SEO pioneer Mike Grehan reviews how keyword placement, then links, and now social signals have affected rankings on the search engines — and what you should be doing now to boost your rankings. In the early days of search engines the primary signal for rankings was getting keywords in the right places on a webpage. Then, beginning with Google, links became the primary signal. Now search engines are looking for signals from end user behavior to deduce what users want. One such user behavioral signal is time on a page or the bounce rate. With a tool bar installed, search engines can now track what you do after the click to gauge engagement. When it comes to social signals, theres a lot of confusion. It isnt about who generates the most tweets. Rather, user-generated content included in rich snippets — such as reviews and ratings — are become important social signals. Mike Grehan is an SEO pioneer. Now he is Global VP of Content for Incisive Media — over content in SES Conferences, ClickZ, and Search Engine Watch. This video interview was recorded at the SES Conference in Chicago on November 15, 2012.