What are cookies ?

Basically they are small pieces of data stored in the web browser when you visit a website, they help the website remember things such as your preferences or pages visited, to read more in depth information about cookies I recommend BBC Webwise / Wikipedia / Information commissioners office

Cookies we use.

PHPSESSID: A session identifier, also called a session ID or session token, is a piece of data that is used in network communications (often over HTTP) to identify a session, a series of related message exchanges. Session identifiers become necessary in cases where the communications infrastructure uses a stateless protocol such as HTTP. For example, a buyer who visits a seller's site wants to collect a number of articles in a virtual shopping cart and then finalize the shopping by going to the site's checkout page. This typically involves an ongoing communication where several webpages are requested by the client and sent back to them by the server. In such a situation, it is vital to keep track of the current state of the shopper's cart, and a session ID is one way to achieve that goal.

The cookies named __utma through __utmz come from Google Analytics, which is used to track website visits. The cookie names likely come from the earlier versions called the Urchin Tracking Module, and are also also by the newer ga.js.

Some specific details:

Also:

Controlling cookies.

To control the way cookies are handled by your browser please explore these instructions for the three main browsers Chrome / Mozilla Firefox / Internet explorer

If you wish to stop Google collecting any of your browsing data via Google analytics you can download and install their own blocking tool here > Google opt out