Google registered the Trademark for "TrustRank" - a possible succesor to the existing PageRank valuation display method that has been said to seen it's end of live as it does not necessarly correlate with the search engine results for several months.

There is a standford research paper available for aprox. a year that outlines the basic idea of the TrustRank algorithm to identify web spam by only a few authorized big seed sites (authority sites?) available at the TrustRank algorithm paper here.

The TrustRank Trademark was registered on March 16 2005 by Google Inc.

Search Engine Watch reported about it in their blog - citing a "Neighborhood Wide Web"

Combating web spam with TrustRank is another interesting read.