A Web Banner or Banner Ad is a form of advertising on the World Wide Web delivered by an Ad server. This form of online advertising entails embedding an advertisement into a Webpage. It is intended to attract traffic to a Website by linking to the Website of the advertiser. The advertisement is constructed from an image (GIF, Flash), often employing animation, sound, or video to maximize presence. Images are usually in a high-aspect ratio shape (i.e. either wide and short, or tall and narrow) hence the reference to Banners.