There are three main ways that people share music on the Web. The first is between friends or relatives. They send you a file; you send them a file. You each need to have a ripper/encoder and a player to trade and listen. There are a number of shareware and commercial products that do this.
Ogg Vorbis is a new audio compression format. It is comparable to the other compression formats—MP3, VQF, AAC, etc.—but different because it is open source and patent free.
Ogg is the name of Xiph.org's container format for audio, video, and metadata.
Vorbis is the name of a specific audio compression scheme contained in Ogg.