Link buying along with link renting are artificial forms of link building and a sub-discipline of SEO in the off-page area. The aim is to increase link popularity using financial resources. Acquiring backlinks through link buying is a direct intervention of link builders. It is therefore the opposite of natural link building.
Backlinks are still an important ranking factor. However, it is important to distinguish between good and bad links. Google strongly emphasizes natural link building and recommends that this should be achieved through high-quality content and updated information. Links acquired by link buying do not indicate anything about the quality of a website. Therefore, Google policy prohibits the purchase of backlinks with financial resources and penalizes this method of link building with a loss in ranking or an exclusion from the organic Google index. This prohibited approach becomes conspicuous with unnaturally rapid link growth and lack of topic relevance to the website. Despite Google’s public avowal against unnatural link acquisition, the practice of link buying on online platforms is still being practiced.
There are many startup companies that do not yet have the necessary contacts and clients to organize a link exchange. For them, link buying is usually the only way to gain a good ranking. Moreover, some topics are geared towards a very specific clientele, and thus you will rarely find discussions in forums on that subject. Increasing link popularity is very difficult to realize naturally in this case. Aside from that, keywords are often fought over hard so that there is no way around link buying.