A reciprocal link is a mutual link between two objects, commonly between two websites to ensure mutual traffic. Example: Max and Ruby have websites. If Max's website links to Ruby's website, and Ruby's website links to Max's website, the websites are reciprocally linked. Website owners often submit their sites to reciprocal link exchange directories, in order to achieve higher rankings in the search engines. Reciprocal linking between websites is an important part of the search engine optimization process because Google uses link popularity algorithms (defined as the number of links that led to a particular page and the anchor text of the link) to rank websites for relevancy.

Three way linking (siteA -> siteB -> siteC -> siteA) is a special type of reciprocal linking. The attempt of this link building method is to create more "natural" links in the eyes of search engines. The value of links by three-way linking can then be better than normal reciprocal links, which are usually done between two domains.

In order to take advantage of the need for inbound links to rank well in the search engines, a number of automatic link exchange services have been launched. Members of these schemes will typically agree to have several links added to all their web pages in return for getting similar links back from other sites.

An alternative to the automated linking above is a link exchange forum, in which members will advertise the sites that they want to get links to, and will in turn offer reciprocal or three way links back to the sites that link to them. The links generated through such services are subject to editorial review.

One way link is a term used among webmasters for link building methods. It is a hyperlink that points to a website without any reciprocal link; thus the link goes "one way" in direction. It is suspected by many industry consultants that this type of link would be considered more natural in the eyes of search engines.

An effective way to build this type of one way linking is by distributing articles through content sites and article directories. These articles generally contain an About The Author box that contains a one-way link back to the author's URL. When publishers use these articles, those one-way links help authors increase their PageRank.

Link campaigns are a form of online marketing and SEO. A business seeking to increase the number of visitors to its web site can ask its strategic partners, professional organizations, chambers of commerce, suppliers, and customers to add links from their web sites. A link campaign may involve mutual links back and forth between related sites, but it doesn't have to require the reciprocation of links.