Last year, a company called Vringo sued Google over a couple of patents, and last week, the case began trial in Virginia. The patents are directly related to AdWords and AdSense, which are obviously vital to Google's revenue.
One patent (6,314,420) is described in the following manner (via Ars Technica):
A search engine system is provided for a portal site on the internet. The search engine system employs a regular search engine to make one-shot or demand searches for information entities which provide at least threshold matches to user queries. The search engine system also employs a collaborative/content-based filter to make continuing searches for information entities which match existing wire queries and are ranked and stored over time in user-accessible, system wires corresponding to the respective queries. A user feedback system provides collaborative feedback data for integration with content profile data in the operation of the collaborative/content-based filter. A query processor determines whether a demand search or a wire search is made for an input query.
The patent was granted to Ken Lang years ago, who sold it to Lycos (also years ago), and eventually bought it back. Lang is now with Vringo, and appears to be greatly interested in getting paid. TechCrunch has a long, detailed version of the story from a friend of Lang's from earlier this year.
The original complaint, which also goes after AOL, IAC, Gannett and Target, says, "Google has used and continues to use search and search advertising systems that adopt the Lang/Kosak Relevance Filtering Technology. For example, Google adopted the Lang/Kosak Relevance Filtering Technology with its use of "Quality Score." Google's search advertising systems filter advertisements by using "Quality Score" which is a combination of an advertisement's content relevance to a search query (e.g., the relevance of the keyword and the matched advertisement to the search query), and click-through-rates from prior users relative to that advertisement (e.g., the historical click-through rate of the keyword and matched advertisement)."
"Google's search advertising systems incorporating "Quality Score" - including products such as AdWords and AdSense for Search - generate advertisements and associated links when end users search from Google's websites including, for example, its main webpage. Google additionally allows third party publishers - via AdSense for Search - to display advertising search results in response to search queries made on the third party publishers' websites. After adopting the Lang/Kosak Relevance Filtering Technology, Google's market share significantly grew and its profits from search advertising considerably outpaced those of other PPC advertising providers. The Lang/Kosak Relevance Filtering Technology proved to be extremely valuable to Google, allowing Google to generate greater profits and to expand its operations into many other technology areas."
The complaint also maintains that Google had knowledge of the patented technology, citing Google's settlement with Overture in the past.
Obviously, the outcome of this case has pretty big implications for the search industry, and just adds to Google's stack of legal issues it has to contend with.
As you can see from the lead image, Vringo is also suing ZTE.