Many people only trade links because they purpose is to increase their search engine rankings. That is the wrong approach.
If you would like to be successful with your linking activities, you should act as if search engines didn't exist. Focus on your web site visitors, not on search engines.
A link partner with a low Google PageRank that has a similar topic like your site will bring you much better visitors than an unrelated link partner with a high PageRank.
If you see a good web site with good content that has a low PageRank you should trade links with that site if that web site is useful for your visitors. One day, that page might have a higher PageRank and it will still link back to you.
Ask yourself: Is the web site related to your site? Would it make sense for web surfers if they linked to you and you linked to them? Could visitors of the other web site be interested in your site? If you find a web site you would love to visit or your visitors would love to visit then link to it and ask for a link back to your site.
Webmasters exchanges links long before search engines included links in their algorithms. The
reason for that is that links can contribute to the success of your web site even if search engines didn't exist.
http://buildlink.blogspot.com/
This post also appear on my earning online blog
Ref:IBP