The Remember Me feature requires the use of a Cookies to store data on your device and by law you must be informed what is stored in any cookies so that you can make an informed choice as to whether to use this feature or not.
The main cookie for this domain is called S3C and it contains your username, password (encrypted), loggedon state, user level and membership number.
The cookie is only used by this site and, if it exists, it allows you to continue using this site in a new browser session on this device (if you didn't logout), and it pre-populates your logon credentials if you do need to logon again. This cookies will expire after 6 month if not used.
Other cookies used are:
Scayt_verLang - (scayt = spell check as you type) this cookie stores language version used and helps the site work faster with text editors as used by the batch emailer.
PHPSESSID - this cookie is native to PHP (the server side code running this website) and it is used to establish a user session and to pass state data. It is a session cookie and as such it disappears when the browser is closed.