iPlayer is a BBC service that allows you to watch TV shows several days after they’ve aired. However, it has been heavily criticised for being tied to Windows and Internet Explorer. In particular since the BBC is a government agency, it has a mandate to be vendor neutral.
Recently BBC announced a version of iPlayer for Mac and Linux (only for the UK). This is iPlayer Desktop and it uses Adobe AIR technology. Personally, I like Adobe AIR very much and I am happy with the news.
Parts of Adobe AIR are proprietary (the runtime), but most of it is open source (WebKit, the VM, SQLite). I would love to see an open source alternative (I have compared AIR with Prism and XULRunner).



