A site wide link is a link which appears on all the pages of your website. There are a couple of reasons to avoid using these if you’re looking to market your website online. The first is repetition. Google and other major search engines will assign PageRank value only once, but it’ll cost you each time Google tests a page.

Your best bet? Avoid links which appear on every page of your website but, if you need to have them, take the time to add a nofollow attribute to your anchor tag so that Google knows those pages are less important and shouldn’t be counted as a link.

A great example of this is your terms of service page or privacy policy. While it may appear on every page (and most likely should), you don’t want to spend your PageRank value linking to each of these.