This is a very useful technology for musical collaborators and remixers: Free Lossless Audio Codec (FLAC) is a popular file format for audio data compression. Being a lossless compression format, FLAC does not remove information from the audio stream, as lossy compression formats such as MP3, OGG and AAC do.
This makes it ideal for Internet based audio collaborations and audio source files for remixes, where numerous audio files need to be up and downloaded between participants.
Standalone FLAC conversion software is free to download and not encumbered by patents as well as multi-platform, so Mac, Windows and Linux users can all benefit from this. In the future, Digital Audio Workstation makers will hopefully incorporate the ability to import from and export to FLAC directly into their software, like some of them have started to do with the OGG Vorbis lossy compression format (a non patent encumbered and free alternative to mp3).
So while using FLAC will introduce one extra conversion step for most people in the short term, it is really worthwhile for those, who want to shorten up and download times dramatically without loss of audio quality. For a typical project I’ve seen compression rates of better than 50%. Impressive stuff for audio.
One more thing: FLAC compression does not suffer from the few milliseconds of silent audio at the beginning and end of mp3 files, which is a pain in the neck to manually fix.