Google Voice Blog: Google welcomes Gizmo5 - completely passed me by: Google has acquired Gizmo5. For a long time, it was a competitor to Skype, based on SIP instead of proprietary protocols. The company's founder was the same Michael Robertson who also founded mp3.com, mp3tunes.com, and Linspire - and often came across as somewhat dubious (especially the winding up of Linspire is still under discussion, as the shareholders largely came away empty-handed). Incidentally, Gizmo5 also used ejabberd for the IM infrastructure - that's how I stumbled upon it.