Cufón is a fast text replacement technology that uses canvas and VML instead of Flash or images, offering an efficient solution for text rendering without requiring additional plugins. It is open-source and hosted on GitHub, where users can find more information about its usage and features. Developed by Chris Wanstrath, known as @defunkt on Twitter, and with contributions from @sorccu, Cufón has gained popularity for its ease of use and effectiveness in web design.