Comment OpenSWF.org (Score 2) 84
The Flash File Format (SWF) has been "open" since April 1998, but the spec was (is) very buggy and poorly supported.
Macromedia announced they would release the source code for the Flash Player in May 1999, but the have been very slow in delivering.
Everything you ever wanted to know about Flash is here: OpenSWF.org
