Here's more evidence that the relevance of link sources is not much of a factor (if a factor at all) in determining the value of an incoming link. A number of very experienced online marketers have left some interesting comments at this post entitled How I Got Shown Up And The Myth Of Irrelevant Links.
In my own experience, what determines the "relevance" of an incoming link is
(a) the anchor text - if the anchor text implies that a source is about "dog training", then who is Google to question that? and
(b) the simple fact that the link is comgin from a legitimate site. If it is a "trusted" source, why would Google question the "relevance" of such a link?
