What do you mean by php cookies?

When you go to a site, the site stores a little file on your computer with notes about your login, last time you were there, what you have done recently, and stuff like that. Your browser has disc space for those cookie files, there is another type called Silverlight cookies, and some other types, each with their own space on your disc. These files can add up to a respectable amount of disc space, all wasted if you never go to that site again. It also takes some time to look through them every time you load a page. You can find various cookie managers and you probably should get one or another for convenience. For instance, if you watch a flick at youtube.com, that is the flick that appears first on the page next time you visit. After a while you might feel like you want to be offered some other choice.