Microsoft's Firefox add-on simply replaces the browser's <video> player with a Windows Media Player object, so the fees have already been paid for as part of th

Microsoft's Firefox add-on simply replaces the browser's <video> player with a Windows Media Player object, so the fees have already been paid for as part of their licence to include an H.264 decoder with all copies of Windows. Supporting H.264 makes sense for Microsoft as a licensor of the patent pool.