The University of New South Wales' school of computer science and engineering has put together a search project that uses del.icio.us tags and a quality metric of the users to deliver search results based on pages that have been tagged at del.icio.us.

The project, Collaborative Rank, ranks users (taggers) by how often the tags they make are similiarly tagged by other users. This measurement is designed to give the best taggers greater input into the search results, helping to produce the most "relevant" search results.

This project is the first I've seen to use folksonomies to produce a real search engine of web pages. It's also a journey into a new realm of SEO, where generating interest and usefulness is more valuable than optimization and link building... either that or who can best spam del.icio.us.