These days Link Popularity is more of a determining factor in search engine ranking than meta tagging. Development of link popularity should be one of the primary activities of any webmaster interested in their website's success.

Link Popularity refers to the number of links pointing back to your site, which offers a look at how many other sites considered the site important enough to link to it. Every link to your site is essentially a "vote" for your site. The value of that "vote" depends solely on the relative value of the website the vote originates from. For a detailed explanation of Google's PageRank algorithm, check out Chris Riding's Google PageRank Explained.

If the site your are considering exchanging links with is Link Partnered with sites that are considered "good company" and are on-topic for the "theme" of your website, then it is a good Link Partner candidate for you. If you are marketing a real estate site, then a biomedical website would not be on-topic, and would not be a good link partner candidate. The name of the game here is relevancy.