Comment spamming (or blog spamming) is a form of search spamming in which random comments, promoting links to commercial services, are automatically posted to publicly-accessible forums, guest books, blogs, message boards, etc.

A common approach to detecting spam web pages is through content analysis based on classification heuristics [2,3]. In this report, we propose an orthogonal context-based approach that uses URL-redirection analysis.

We(Microsoft) call our(this) approach the Search Defender approach.

http://research.microsoft.com/searchdefender/