From now on, any video you upload to YouTube will be transcoded into Google's WebM codec, joining the "videos that make up 99% of views on the site or nearly 30% of all videos." Google explains it to the non-tech savvy folk like so:

"If you travel abroad frequently, you know that charging your electronic devices is not always an easy task. Power adapters for cellphones and computers don't always fit into local power outlets, meaning you have to pack converters. Think of video on the web in a similar way. Currently, there are countless devices used to record videos and hundreds of different video file formats. Even more, certain web browsers that you use to view video online only accept certain ‘codecs' - or programs used to encode, transmit and playback video files - and others require plug-ins (converters) to integrate the video file with the browser.

Despite these complexities, one of our key aims is to deliver great content to you wherever you are - regardless of device, browser or other technical specification, so you never have to remember that complicated "power adapter converter" to watch a video.

To that end, all new videos uploaded to YouTube are now transcoded into WebM. WebM is an open media file format for video and audio on the web. Its openness allows anyone to improve the format and its integrations, resulting in a better experience for you in the long-term. As we work to transcode more videos into WebM, we hope to reduce the technical incompatibilities that prevent you from accessing video while improving the overall online video landscape."

For the remaining 70 per cent of backlog they haven't managed to do yet, they'll still be serving videos in the H.264 codec, as well as developing their HTML5 video player. [YouTube Blog]