what is the Firefly media server?
Unfortunately, no one can be told what the Firefly media server is. You have to see it for yourself. This is your last chance. After this, there is no turning back.
No. Wait... wrong story.
The Firefly Media Server is the open-source project that was mt-daapd. It continues to be open source, and the most fundamental difference is support for RSP, the Roku Server Protocol.
As far as what the capabilities are of the Firefly Media Server, these are the same capabilities of mt-daapd itself. On the unix version of Firefly, it supports wma, ogg, flac, alac, and can transcode on the server side. These features are still to be enabled on the windows side, but we hope to be able to support these features shortly.
will there be a Linux version?
Absolutely. As this is based on mt-daapd, it remains open source, and as such, linux and other unix platforms will continue to be supported.
The biggest win is that an open source server has the ability to have features demanded and added by the community. You have a say in the direction of the development, and can influence what it does and how it works.
So I'd encourage you to make suggestions, report bugs, and help make Firefly the best media server available for the soundbridge.