Data mining query logs? Then these research papers might interest you.

Ji-Rong Wen, Jian-Yun and Hong-Jiang Zhang:
Query Clustering using User Logs ACM Transactions on Information Systems (ACM TOIS), 20(1), 59-81, January, 2002
Hang Cui, Ji-Rong Wen, Jian-Yun Nie and Wei-Ying Ma:

Query Expansion by Mining User Logs

IEEE Transaction on Knowledge and Data Engineering, Vol. 15, No. 4, July/August 2003.



Gui-Rong Xue, Hua-Jun Zeng, Zheng Chen, Wei-Ying Ma, Hong-Jiang Zhang, Chao-Jun Lu:

Implicit Link Analysis for Small Web Search

SIGIR Conference, 2003.