Gary Price at ResourceShelf points out an online version of the Dec 2006 SIGIR Forum publication.
I was reading it on an airplane a couple weeks ago and had been meaning to write about it. The paper Gary highlights, "A Reference Collection for Web Spam" (PDF), is a good introduction to WEBSPAM-UK2006 collection that Yahoo Research has made available of hand-labeled spammy and non-spammy web pages.
I also enjoyed the SIGIR Workshop reports, especially the AIRWeb summary, "Adversarial Information Retrieval on the Web" (PDF), and the notes from a session on exploratory search, "Evaluating Exploratory Search Systems" (PDF).
For more on AIRWeb at SIGIR 2006, see also my previous posts, "Blog spam at AIRWeb" and " Web spam, AIRWeb, and SIGIR".