Ways of using $_COOKIE in procedural PHP


I am still learning PHP and I could use info on what are the most common usages / applications of $_COOKIE in the most common types of scripts like cms / blog / tube / forum / online store. I know how cookies work, but these actual applications (maybe like 10 or more) would be what I would actually need and then use the info for practicing it.

I basically need to “uncover” _SESSION and _COOKIE more, these actual usages of it, applications, in procedural PHP.



Answer: Anything that both the server and client need to hold on to.

Additional: Anything that should persist beyond the length of a single session.