(Rich Internet Application) Fully featured software package that runs in a browser. Early generations of Internet-hosted, browser-based applications were notoriously basic compared to equivalent software that ran on a Windows or Mac desktop. This led to the evolution of RIA platforms (also known as rich client platforms), which boost the core functionality of the basic browser by temporarily downloading extra software to the client. This makes it possible to develop applications with the look and feel of a full-fledged Windows or Mac application, making them faster and more convenient to use. RIAs are distinct from 'smart clients', which require extra software pre-installed on the client machine. The leading RIA platforms today are AJAX, based on JavaScript and XML messaging, and Adobe Flex, based on Macromedia's Flash technology.