There are two basic types of backlinks, and one is more valuable than the other. Let’s take a quick look at each one and how they affect your site.
A Nofollow tag tells search engines to ignore a link. They don’t pass any value from one site to another. So, typically they aren’t helpful in improving your search rank or visibility.
Dofollow links are the type of backlink that everyone wants. Just keep in mind that those coming from respected sites hold the most value. This kind of backlink can help improve your search engine rankings.
However, there are dofollow links that are considered being bad or ‘toxic’. These links come from suspicious sites or are gained by breaking the search engine terms of service.
This may cause Google to penalise or even de-index your site. Remember, it’s not about the quantity of backlinks, but rather the quality that makes the difference in ranking.