MrFewkes - 9:20 pm on Nov 19, 2011 (gmt 0)
The spam links from my network are totally and utterly placed on my sites for the sole purpose of increasing my SERP ranking. They are text links placed within paragraphs of text on static HTML pages which sit there for years and years. I never bother to check any relevance of the text on the linking page to the page the link goes.
Spam because they exist ONLY for SEO.
Hope this helps :)