One of the papers that will be presented at the conference: Web Spam Taxonomy, by Zolta Gyongyi and Hector Garcia-Molina from the Stanford Database Group has been updated and is now available full text (9 pages; PDF) online.
It's a very interesting read.
From the abstract:
Web spamming refers to actions intended to mislead search engines into ranking some pages higher than they deserve. Recently, the amount of web spam has increased dramatically, leading to a degradation of search results. This paper presents a comprehensive taxonomy of current spamming techniques, which we believe can help in developing appropriate countermeasures.