Firefox 2 has just been released. Congrats to Mozilla and all the people involved, I am a very happy user since 1.0.
One of the interesting new features is a way of subscribing to feeds with your newsreader of choice. Beginning with the next version 1.2.3, RSSOwl on Windows will show up in the list of readers and subscribing to feeds out of Firefox will be supported.
Update: Of course this feature is available on other platforms as well. However, only Firefox on Windows is able to show RSSOwl automatically in the list of readers. But you can always add any reader by selecting "Choose application..." from the list.