The Vorbis audio codec is well worth using: slightly better compression/quality than AAC, and natively VBR. It's widely used in commercial video games. Unfortunately for consumer use, the native container formats are awful, the decoder is computationally expensive, and it can't do CBR.<p>On the other hand the Theora video codec has nothing going for it technically: it's worse than any of its competitors across the board. It was written for the commercial market, but was abandoned after no customers ever bought licenses. There are no independent implementations: there's only a transliteration of the decoder to Java, and a fork of the encoder to not suck quite as pointlessly within the bounds of the spec.<p>Theora's few proponents are pushing it for purely ideological reasons. Has that ever worked?