Macromedia Flash is a popular, proprietary program for creating interactive Web content, such as short videos, banner ads, and even full-featured games. It is one of the most widely used programs of its kind, and its Flash player is estimated to be installed on 97% of Internet-connected computers.
Ultima Linux includes the Flash Player plug-in for Firefox in the XAP series, as part of the firefox-plugins package. (The Flash program used to create content is not available for Linux systems.)