Google's Personalized Search Shifts SEM Landscape

With the expanded implementation of its Personalized Search, Google has quietly but significantly altered the search engine marketing (SEM) playing field, according to Search Engine Land (SEL).

Because Google now weighs a variety of new and ever-changing variables in determining what to return for a search, some established SEM techniques no longer apply, or at least must be altered.

Google's algorithm now takes into account searchers' click history as well as their Personalized Homepage when it returns search results. The changes are designed to offer results that are more useful to the searcher, with each new user behavior becoming a new factor in future searches.

For search engine marketers that means the days of trying to divine that one secret formula for scoring high among search results are now gone. Now there are an unlimited amount of variations in search results even for a single search term, because search results in part depend on the click history of each user.

Also being factored into returning search results are the types of sites in users' Google Bookmarks, a social tagging tool analogous to del.icio.us. SEL speculates that Google Reader feed subscriptions or feed click history are not being used for Personalized Search, but the RSS aggregator could provide yet another data set for Personalized Search.

SEL provides tips on how best to approach optimization in this new search world, in general ensuring that sites are optimized for Google's services, specifically, and social search and social networking, in general.