Cookies
Cookies are small files that your browser stores at the behest of websites. The website which created the file(s) has access to them when responding to your attempt to view a page, and usually stores information which can allow it to identify your account in order to personalize the page response.
The KCK Farms site uses a single cookie to determine which account, if any, you have used to log in.
You may wish to reference Google's instructions on how to enable cookies, or Wikipedia for a more detailed description of cookies.