The Apple Lossless Audio Codec was developed by Apple and has been used on all of its platforms and devices for some years now. Similar to other lossless audio codecs, the ALAC offers audio compression without any loss in audio information. These lossless formats typically are not as small in file size as MP3s, which contain a loss of information with each generation.
One key advantage of ALAC over other codecs is that it is supported on all of Apple's devices--such as Apple's iPods and iOS devices. With this codec becoming open source, it means that new technologies can be spawned from this core tool--both for creation and playback of audio.