Reciprocal linking means that two websites link to each other so that users who visit one site can be directed to the other. Healthy reciprocal links are also appreciated by users, as they can jump to pages related to the page they visit.
However, in the past, there was a time when the number of backlinks was directly linked to the page rank, and many website owners ignored the user’s perspective and scattered reciprocal links. There were even services that allowed you to “buy” reciprocal links.
Nowadays, Google’s large-scale algorithm update called Penguins Update has no backlink effect, and it can be said that it has the opposite effect, and SEO measures by mutual linking have become meaningless.