Again, Loren Baker posts a thread at Search Engine Watch Forums named Google to Manipulate Organic Rankings with User Profile. In that thread, he summarizes a patent application named Personalization of placed content ordering in search results.
A system and method for using a user profile to order placed content in search results returned by a search engine. The user profile is based on search queries submitted by a user, the user's specific interaction with the documents identified by the search engine and personal information provided by the user. Placed content is ranked by a score based at least in part on a similarity of a particular placed content to the user's profile. User profiles can be created and/or stored on the client side or server side of a client-server network environment.
Loren explains that this is different then a Google AdWords patent, because this affects the core organic results. He expands; Such profiles are created by Google and gathered from previous queries, web navigation behavior via tracked links and possibly sites visited which serve Google ads, computers with Google Applications installed such as Desktop Search, Google Wi-fi Connection or Sidebar, and personal information which Google identifies which may be “implicitly or explicitly provided by the user.” Loren wrote a Search Engine Journal article on it named Google Patent : Organic Results Ranked by User Profiling with more information.
Forum discussion at Search Engine Watch Forums.