Here's info about a one patent recently awarded to Yahoo on determing similarity between documents along with recently published patent application by Microsoft dealing with browsing info on the mobile web.
U.S. Patent Awarded to Yahoo
Title: Method and apparatus for measuring similarity among electronic documents
Awarded: Jan 24, 2006
Filed: June 14, 1999
A method and apparatus are provided for determining when electronic documents stored in a large collection of documents are similar to one another. A plurality of similarity information is derived from the documents. The similarity information may be based on a variety of factors, including hyperlinks in the documents, text similarity, user click-through information, similarity in the titles of the documents or their location identifiers, and patterns of user viewing. The similarity information is fed to a combination function that synthesizes the various measures of similarity information into combined similarity information. Using the combined similarity information, an objective function is iteratively maximized in order to yield a generalized similarity value that expresses the similarity of particular pairs of documents. In an embodiment, the generalized similarity value is used to determine the proper category, among a taxonomy of categories in an index, cache or search system, into which certain documents belong.
Microsoft Patent Application
Title: Mobile information services
Filed: September 15, 2005
Mobile communications devices display contextually relevant information based on the presence, status, and identification of a user. Lens templates control how the information is displayed and can be customized and designed for specific usage profiles. The lenses that are used can be updated at any time to accommodate changes in a user's presence. The granularity of the lenses and corresponding information can also vary to accommodate different needs and preferences. Lenses can also be specialized for different events or venues. The lenses allow a user to access contextually relevant information from a mobile communications device having limited display and/or browse capabilities without requiring a user to navigate through undesired information, wasting valuable resources in the process.