When the MP3 standard was first adopted in 1991, it was designed to be used in digital radio broadcasts, optimizing data compression while still producing a sound faithful to the original. Few at the time imagined the firestorm of controversy the new file format would create.

     The first song to be encoded as an MP3 was Suzanne Vega's "Tom's Diner", encoded simply as a test by engineer Klaus Brandenburg in order to assess the efficacy of the new format.

     In 1995, once the first publicly available MP3 encoding software was launched, the phenomenon of music sharing also reared its head. The Internet Underground Music Archive (IUMA) had previously been operating as a repository of available music in MP2 format, but it was not until MP3 finally hit the 'net that the explosion occurred. Initially, people began posting files of their favorite tunes on the Web for download. The development of the WinAmp player in 1997 came as a milestone, allowing people to manage a library of MP3 files.

     The inevitable happened in 1999, when the file-sharing service Napster was launched. For the first time, a freely downloadable utility allowed Internet users to search from hundreds of thousands - and subsequently millions - of shared music files. Similar sharing services were subsequently launched, including (but by no means limited to) Scour, KaZaA, Morpheus and AudioGalaxy.

     The record companies, represented by the Recording Industry Association of America (RIAA) responded with a flurry of copyright-infringement lawsuits, primarily targeting the companies making the software but also certain users responsible for high-volume sharing of files.

     In the end, the legal pressure was too great, and many of these services folded. A number of services are still known to be operating, though their use is considered to carry at least a misdemeanor charge in many areas, and each week brings a new report of a lawsuit filed against someone still holding onto these methods.

     Thus it became the turn of the legal music download. Perhaps the best known of these is Apple Computer's iTunes Music Store, which allows subscribers the opportunity to download songs individually for 99 cents apiece (or similar value in other nations). Other such enterprises include eMusic, Rhapsody and MusicMatch. Some models allow unlimited downloads for a monthly fee, others work on a song-by-song basis.

     An obvious advantage to the phenomenon of digital music is that the amount of plastic and paper used in packaging. Another is the inherent ability for the customer to pick and choose individual songs rather than purchasing an album in its entirety. This is, of course, a problem for the record companies, who use album sales as the primary metric against which to measure success or failure.

     Some have referred to digital music as a revolution. Some prefer to call it evolution. In either case, it's here to stay.