Cookies uses cookies. You should know about the cookies. Here's the information about the cookies.

A unique identifier for the current user session, set and required by the software this website runs on (in code land, it's the same as a PHP session id).

To better understand how many people use the site and how exactly they use it, the site uses Google Analytics, which sets a number of cookies.

Google uses this to distinguish users.
Google uses this to throttle request rates.
Google uses this to distinguish users.

You can read more about how Google Analytic's uses cookies on their developer website.