Every webmaster who has dabbled in SEO knows that search rankings are all about the links. The more links that come to your site, the more important the SE's consider your site to be. Reciprocal link exchanges seem to be a thing of the past, since having as many outgoing links as incoming theoretically equal each other out and you've done nothing but spend a lot of time on nothing. Search engines are getting smarter, and one-way links are more valuable.