An MP3 blog is a type of blog in which the creator makes music files, normally in the MP3 format, available for ownload. They are also known as "musicblogs" or "audioblogs". MP3 blogs have become increasingly popular since 2003. The music posted ranges from hard-to-find rarities that have not been issued in many years to more contemporary offerings, and selections are often restricted to a particular musical genre or theme. Some MP3 blogs offer music in Advanced Audio Coding (AAC) or Ogg formats.