New CD releases are probably going to one day go the way of the dodo as digital distribution of music becomes a larger part of how music fans consume their music. Compact discs, or CDs, were developed and popularized in the 1980s, effectively replacing cassette tapes and vinyl records as the medium for recorded music. Digital outlets like Apple's iTunes Music Store have threatened CDs as the dominant format for music listeners, but the majority of listeners still get their music on a CD.
New CD releases can be new albums from brand new artists looking to make their mark on popular culture, sometimes gaining popularity through underground movements now prominently created by bloggers.
Some new CD releases come from legendary artists – or at least veteran artists — continuing to add to their legacy (whatever that may be) with new music. There's also been the increasingly common and controversial tactic of record companies repackaging older albums and re-releasing them. There are also all those "Greatest Hits" albums that collect the popular songs from popular (and not-so-popular) artists.
Fans looking for New Album releases can turn to industry news outlets like Billboard. There are also a host of upstart web sites and bloggers who do their best to cover the vast number of releases added to store shelves every day.