A three-way link exchange refers to a kind of reciprocal link exchange among three domains instead of two. A reciprocal link exchange that is so popular today among webmasters is mostly a two-way linking.
Although there is a benefit in exchanging links in terms of SEO, it is said that search engines might not think such links are “natural”. While linking to another website is the core of the Internet, and this net is really built with millions of links, creating the dynamic of network, excessive reciprocal linking could be considered as a link scheme such as link farms.
To make reciprocal links look more “natural”, you can try a three-way link exchange.
In normal reciprocal link exchange, you and your link partner exchange links with each other. Search engines can easily find that out. So, if you have many reciprocal links going in and out, each linking may not be weighed for the maximum value; thus your website may not increase PageRank faster.
In a three-way link exchange, three different domains must be involved. For example, site A links to site B, but not B to A. So, site B is only receiving a one-way link from site A and NOT linking back to it. Likewise, site C and site A are linked from one site but not linking back. Instead, site C and A are simply reciprocal-linking to different domains.
The way to create more natural links in a three-way link exchange is done by using a set of three one-way links. A, B, and C are only receiving one-way links, and they do not directly link back.