Pay for backlinks
Backlinks are a very powerful and, at the same time, very challenging SEO tool: it means being able to obtain links from other websites that point to yours, precisely because your site is considered valuable .
Link building becomes bad when you have to pay a company that sells links at a cheap price to get a backlink . Why? Very often the links come from spam sites created specifically for this practice.
As with keywords, with the algorithm update, Google now cares about checking the authority of the sites where your backlinks are hosted, giving priority to quality over quantity . This is why low-quality links harm your website: focus your strategy on building legitimate links.
It is a practice also called cloaking , now little used, which consists of inserting the various keywords into the page making them visible to search engines but not to the human eye , or hiding them in the page code or making the color uniform so as to confuse them with the background.
In both cases, it is counterproductive because your page will rank for keywords that do not concern the actual topic discussed, leaving your visitors dissatisfied and they will exit the navigation, penalizing you.