An article from discussing a patent application recently filed by Google reportedly covering part of its relevancy algorithm.  The author draws the following conclusions as to how Google determines freshness, one of the components of relevancy:

• The frequency of all web page changes
• The actual amount of the change itself… whether it is a substantial change redundant or superfluous
• Changes in keyword distribution or density
• The actual number of new web pages that link to a web page
• The change or update of anchor text (the text that is used to link to a web page)
• The numbers of new links to low trust web sites (for example, a domain may be considered low trust for having too many affiliate links on one web page).
Although there is no specific number of links indicated in the patent it might be advisable to limit affiliate links on new web pages. Caution should also be used in linking to pages with multiple affiliate links.