A short code is a telephone number used for easy text messaging, with automated responses. Short codes are purchased similarly to web domains. They are used by corporations for promotional purposes, to hold sweepstakes, reward systems, selling products, and distributing information. Short codes can cost thousands of dollars per month, depending on whether the numbers spell a useful word. Such words are usually between 4 and 6 letters long. Other companies use numbers that are easier to remember.
COKE - 2653 - rewards - mycokerewards.com
41414 - contests - 41414.com
FBOOK - 32665 - interacting with facebook.com
GOOGLE - 466453 - interacting with google.com
there are also countless short codes that subscribe to to ringtones, wallpapers, and other tools for your cellphone, with a monthly fee