Any hyperlink to a webpage from an external website is known as a backlink or inbound link. Backlinks are important to website owners as they help determine how Google, and other search engines, determine Page Rank.
The more backlinks a website has from other reputable websites (also known as authority websites), the higher a website’s perceived authority. Google uses backlinks, although it is not the only factor, to help determine how a website is ranked on its search engine result pages (SERPs).
In general there are two types of backlinks: “do-follow” and “no-follow”.
If a website about health includes a “do-follow” link to another website in one of their blog-posts, they are telling their readers that they think the website they have linked to is worth reading, well-written, and an authority. Backlinks that are “do-follow”, are considered as votes of approval. Google, and other search engines, therefore count this as a valid backlink.
On the other hand, a “no-follow” link means that while you are linking to a website, its authority is one you are unsure about, or not recommending. An example of this could be the links people leave I comments on a blog post, which most website set to be “no-follow”.
Google has made it very difficult for people hoping to boost their search engine rankings by buying spammy backlinks by updating their algorithm, as the recent changes in search algorithms have made it more important to gain “do-follow” backlinks through honest means. This requires companies create useful content that people want to share and link to. Previously, SEO companies were creating spam backlinks by mass-posting on forums, in comment sections, or even setting up fake websites. Currently, most social media tools use “no-follow” links which are not included in the total backlinks a website has.
Here are some examples for HTML codes for “do-follow” and “no-follow” backlinks below: