One of the big issues for people trying to move to a completely open source life is how to deal with proprietary file formats. While there are plenty of ways to read things like Microsoft Excel files with open source applications, other formats have been harder to crack. One particular priority for the Free Software Foundation has been creating a truly free player for the Macromedia Flash format. With a beta release a few days ago, the Gnash project is making good progress on filling that niche.
As of version 0.82, Gnash is officially in beta. While it does not have 100% compatability with the most recent Flash releases, it does support Flash through version 7, with partial support of versions 8 and 9. It can run as a standalone player, or as a plugin for Mozilla- or Konqueror-based browsers.
Does it matter? Well, if you want to interact with the full Internet, it does. Between web sites with fancy navigation and online video sites, the various Flash file formats are more pervasive than you might expect. Hardcore open-source users have had to either avoid these sites entirely or use a non-free alternative to view them. While Gnash certainly has a ways to go to be a perfect drop-in replacement for Flash, it's under active development and works well enough to view many Flash files.