Link exchange
Backlinks are recommendations on the World Wide Web and show search engines like Google whether content is valuable to users. Because good links are hard to come by, link exchanges were very popular among website owners for a long time: two partners agree to link to each other. Today this is risky, because excessive link exchanges violate Google's spam policies.
Why links are relevant for search engine optimisation
The value of backlinks in search engine optimisation rests on a simple assumption: a page linked by many other websites is probably helpful and trustworthy. For example, someone who finds a guide particularly good and recommends it to their readers sets a link. If such voluntary recommendations accumulate, Google sees this positively – and that can improve rankings.
Because links are so important, many website owners put quantity before quality. Link exchanges were practised on a massive scale, often via link farms, link directories and exchange platforms that anyone could join. For a long time, that worked. Today, Google explicitly counts excessive link exchanges – “link to me and I'll link to you” – among link spam practices, as well as unlabelled paid links.
When the penguin eats the links: link exchanges are no longer so easy
With the Penguin update in 2012, Google began to consistently detect and devalue unnatural links; since 2016, this has happened in real time. Links from directories and exchange networks have hardly brought anything since. Google pays attention to whether links come from high-quality websites, whether the topics match and whether a link offers users genuine benefit. Placing your beekeeping website on a page about surfing in Hawaii won't impress Google. But even topically relevant exchange links stand out if they are set systematically and in large numbers.
Links that arise from a genuine relationship and help users, on the other hand, are unproblematic: a manufacturer links to its retailers, a shop to the manufacturer of its products, two companies with a joint project link to the respective project page. Such links look natural because they are.
It becomes problematic when links are exchanged purely for the sake of links – whether directly reciprocal, via a third website (triangular exchange) or via entire networks. Google generally recognises such patterns and devalues the links. In the worst case, a manual action is taken against the website.
Take a close look: avoid bad neighbourhoods
Every website you get a link from or link to should be reputable. Sites from questionable areas such as illegal gambling or spam, sites that openly sell links or sites that have evidently already been devalued by Google are not a good neighbourhood. Links from such a bad neighbourhood can harm your own website.
Another warning sign is heavily optimised anchor text: link profiles in which most links carry the same keyword anchor text look unnatural and were specifically devalued as early as the Penguin update.
Conclusion on link exchanges
Systematic link exchange is no longer a recommendable route to better rankings today. It violates Google's guidelines, brings little at best and can do harm at worst. There is nothing wrong with links between genuine partners, however – as long as they make sense for users and aren't set by arrangement purely for rankings. The sustainable route to backlinks remains creating content that others recommend voluntarily.