It is an HTML tag used in web page design that allows the designer to comment within the code of a web page without being viewed in a browser. It is very useful for a designer to communicate with other designers working on the same website. The comments tag was created simply to make comments that are invisible to all but encoders. It is used anywhere within the code of a web page in the following way: <! - - Here you can write a comment that will be invisible to the public - -> There are web page optimizers that recommend using keywords within these comment tags. We in Superior Positioning doubt the effectiveness of this practice. The main search engines know the purpose of these labels very well and we do not think they give them much importance. Well they were not created for netizens surfing the web but for coders. And although we do not believe that a search engine penalizes a website that uses keywords within these comment tags, the time it would take to create them can be better used for more important things that really add value to our websites.