wheel - 10:55 pm on May 21, 2010 (gmt 0)
cnvi is of course, correct.
There's two primary ways to define relevancy of a link pointing at your site. First (not neccessarily in this order) is the content of the page or site that is linking to you. If I had to guess, I'd say that page is the important one.
Secondly is their backlink profile. If their backlinks are relevant - however that's defined- then a link to you should also be relevant. I don't know if Google measures this.
In the end, this ties in with what appears to be an outdated concept of neighborhoods. Go get links from where your competitors get links. I no longer subscribe to this notion.
My backlink profile is highly relevant but does not share the same profile as my competitors. I try and get backlinks from high end authority sites in my niche, ones that others don't have links from. I also work on niches that are very relevant to mine and touch my niche - but again are not areas that anyone else in my niche seems to use. For example, there are technical experts who design the product I offer. I target those technical experts including their licensing/authorization/gov't orgs even though they're manufacturing and I'm retail. Like being a PC retailer and getting links from Intel. Can google figure this? I dunno, doesn't matter. If not now, they'll get there.