The Internet itself is nothing more than a network of links, and mutual linking is a big part of that. Outbound links on your site can hurt your link popularity if they are of low quality and/or unrelated to your site's content. Incoming links from low quality or unrelated sites are a waste of time unless you are just trying to get your site crawled by search engine spiders for the first time. When exchanging links, look at the PageRank value of the partner's home page, as well as the page your link will appear on; Make sure the page is indexed by the major search engines; Don't exchange with a page that has 100 or more outbound links on it; Make sure your link uses important keywords in its anchor text and is surrounded by relevant plain text. Link exchanges have the possibility to be a big part of your link campaign if potential partners meet a strict criteria for SEO.