The concept of out-of-home messages is not new. Billboards, window treatments and point-of-purchase displays are widely used for out-of-home advertising, while bulletin boards (both traditional and electronic), flyers, faxes, memos, and email have been used to send corporate communications and educate employees for decades. However, true dynamic signs first came into popular use with the advent of in-store closed-circuit television networks in the 1970s. With the widespread availability of affordable VCRs, retail stores and corporate headquarters were able to play back pre-recorded content to their patrons and employees, providing timely information and entertaining content. Soon, closed circuit networks would be augmented (and in some cases, supplanted) with affordable TV/VCR combination units for smaller displays, and projection screens and video walls for eye-catching, large format presentations. With satellite distribution, it even became (relatively) affordable to syndicate the same content to thousands of sites at once.