Exchanging links with other webmasters used to be a simple process: You found a site you liked, placed a link to it somewhere on your site, then emailed the site owner asking for a link from his/her site back to yours in return. And quite often they would reciprocate. But it simply doesn’t work that way anymore.
Back in the day, increasing a site’s search engine rankings depended for the most part on getting tons of backlinks pointing to your website, and it really didn’t matter a great deal about the quality or relevance of the links. If you got enough links pointing to your home page Google would reward you with higher search engine rankings.