Backlinking used to be given a great deal of importance up to about a decade ago. This practice, which is classified as being a Black Hat SEO technique, helps to have a website ranked in a better way. Off page SEO done by buying backlinks is considered to be a rather effective way of generating more exposure for your site. However, some argue that paying for a backlink may not always lead to the best results.
Hence the importance of only buying quality backlinks, as at the end of the day you need to make sure that your site is also looking good in the eyes of search engines. The truth is that links can actually hurt you as much as they could help you do better. Backlinks may seem to be a bit of an old school practice, but they are still being used by many these days, despite the fact that there are also other methods that can be utilised to attain the same or similar objectives. However, we all agree that backlinks help in SEO. Anybody having a site will do his or her best to generate backlinks from various sites, and there are many who buy backlinks too.
However the most important aspect in all this lies in the type of backlinks that are being built, and there are indeed several factors which have an impact on whether a backlink is a good one or a bad one.
The subject is quite vast but let us focus on some key elements. As you know a backlink is a link which goes from an external URL to lead to your site. So, if another site then links to a page on your site, you receive a backlink. This works quite well for SEO, and for several years, many top ranking sites invested time, effort and money in generating huge amounts of backlinks from other sites. However the problem here was that they gave very little importance to the quality of such backlinks. In time this led to spammy sites, and backlinking was often classified as being a rather bad way of improving SEO. In time Google even updated its algorithm so as to see to the quality of backlinks.
Hence, while buying backlinks might seem to be old school, in reality it is still an effective SEO method, which however needs to be used with caution and care as the quality of the backlinks is ultimately more important than the number of backlinks.