Say you want to drop a link on a site with a high PR, for the discussion let's say PR7. OK, will that link really help you? Before we discuss that, there's two ways that a link can help 1. The link may pass link juice (PR) to your site 2. The link may enhance the authority of your site for the term you're trying to rank for Passing link juice is pretty well understood. Your site gets, through the link you place on a page, some of the PR that is assigned to the page where the link appears. Add enough such links, and your site (actually the page where the links point) acquires some PR. Authority is a complicated concept, but to simplify, there's two kinds of authority: 1. General authority. Examples of sites that have general authority: wikipedia, blogger, squidoo, ezinearticles, etc. 2. Niche authority. For each niche, there's a few sites that google considers as authority for that niche, and then google ranks these sites on page 1 for terms associated with that niche To get a list of the most generally authoritative sites, just look at the top 1000-2000 sites as listed by alexa. That should give you a pretty good group of general authority sites. When evaluating whether a site is a niche authority site, simply follow these steps: 1. Look at the front page and find the meta keywords tag. Note the keywords that the author of the site thinks are relevant to the site. 2. Now for each keyword, check if the site, or some page on it, rank on the first page of results for that keyword. Yes -> authority, No -> probably not. Very simple indeed. OK, now to the benefits. When google computes the relevance (== authority) of your site for a specific search term (== keyword), it looks at the general authority, niche authority, and anchor text of the link. The first two attributes of the link are computed via some secret formula from the page and site on which the link appears. The last component -- anchor text -- is the text that appears on the link. It is under your control, and so if you want to rank for "blue widgets" then you need lots of links with that anchor text from general authority sites as well as niche authority sites. Now you also understand why getting links from general authority sites that are not relevant to your niche does actually work. By virtue of appearing on a general authority site, your link acquires a little bit of that authority. Add enough links with good anchor text from general authority sites, and your site acquires authority for the keyword(s) in the anchor text. Hope this helps.