I have personally been placed on some kind of mailing list in which I routinely receive offers to exchange links with another pagerank 2 site. A visit to the site invariably reveals a large number of outbound links to other sites. You may receive solicitations like this as well. Is it a good idea to take such a site up on its offer?
A link farm may exchange links with hundreds of other sites solely for the purpose of increasing link popularity. In other words, it’s a form of spamming, and any site that associates with link farms is in danger of being penalized by the search engines.
Link farms originated due to the fact that search engines rated sites based at least partially on its link popularity. In the early days, some search engines even had a limited number of listings, and sites with a small number of inbound links were as a result purged from their index. Therefore, it didn’t take long before a number of operations sprang up to automate the process of exchanging links.