www.hotelkatari.com, like many other commercial websites, uses a standard technology called 'cookies'. Cookies help a website determine that a user has previously visited the site, as a result, the cookie helps the site save and remember the preferences that have been set while the user browses the site.
Cookies are small text strings that websites can send to your browser. They can not retrieve any other data from your hard drive, or get your email address. If you are simply browsing www.hotelkatari.com, a 'cookie' can be used to identify your browser as one that has visited the site before.