Create a free, open source implementation of the Google algorithm. A source for this algorithm is the paper by the founders of Google:
Sergey Brin and Lawrence Page. The Anatomy of a Large-Scale Hypertextual Web Search Engine http://www-db.stanford.edu/~backrub/google.html
Also, it might be possible to combine some variant of the Google algorithm with the scholium system to search documents created using that system. --rspuzio 13 July 2005