So the cookie on this site is a string of information that stores your visit to my blog on your (the visitor’s) computer, and that your browser provides to the website each time you return. (Unless you clean your cache or have your browser set to private, in which case the site will think each visit is your first one.)
As a rule, cookies will make your browsing experience better. Cookies are a small text files that are placed on your machine to help the site give a better user experience. In general, cookies are used to keep user preferences, store information for things like shopping carts, and offer anonymised tracking data to third-party applications like Google Analytics. However, you may prefer to disable cookies on this site and on others. The most effective way to do this is to disable cookies in your browser. I suggest consulting the Help section of your browser or taking a look at the About Cookies website which offers guidance about how to do this.