Exchanging links is a long established method of increasing web popularity among search engines.
The practice of exchanging links has changed over the years and now requires more thought and attention than before.
As with all search engine optimisation practices it is better to seek links from websites that are more likely to actually refer visitors as opposed to having your link buried among hordes of other sites.
Websites related to your field are often considered most suitable and long term strategic partnerships can be forged in this way.
2seo can source suitable link exchange partners for your site and slowly build and establish a database of quality sites.