Before 2007, the .ogg filename extension was used for all files whose content used the Ogg container format. Since 2007, the Xiph.Org Foundation recommends that .ogg only be used for Ogg Vorbis audio files. The Xiph.Org Foundation decided to create a new set of file extensions and media types to describe different types of content such as .oga for audio only files, .ogv for video with or without sound (including Theora), and .ogx for multiplexed Ogg.
As of November 7, 2017, the current version of the Xiph.Org Foundation's reference implementation is libogg 1.3.3. Another version, libogg2, has been in development, but is awaiting a rewrite as of 2018. Both software libraries are free software, released under the New BSD License. Ogg reference implementation was separated from Vorbis on September 2, 2000.
Because the format is free, and its reference implementation is not subject to restrictions associated with copyright, Ogg's various codecs have been incorporated into a number of different free and proprietarymedia players, both commercial and non-commercial, as well as portable media players and GPS receivers from different manufacturers.
It is sometimes assumed that the name "Ogg" comes from the character of Nanny Ogg in Terry Pratchett's Discworld novels, but the Ogg developers say that is not true. Ogg is derived from "ogging", jargon from the computer game Netrek, which came to mean doing something forcefully, possibly without consideration of the drain on future resources. At its inception, the Ogg project was thought to be somewhat ambitious given the power of the PC hardware of the time. Still, to quote the same reference: "Vorbis, on the other hand is named after the Terry Pratchett character from the book Small Gods".
The Ogg Vorbis project started in 1993. It was originally named "Squish" but that name was already trademarked, so the project underwent a name change. The new name, "OggSquish", was used until 2001 when it was changed again to "Ogg". Ogg has since come to refer to the container format, which is now part of the larger Xiph.org multimedia project. Today, "Squish" (now known as "Vorbis") refers to a particular audio coding format typically used with the Ogg container format.