There are of course exceptions like Jeff Bezos who continues to run Amazon.com. The more common scenario is that of Google where they brought in Eric Schmidt to run the show while Larry Page and Sergey Brin focus on other projects. As Tesla has grown rapidly over the past year and a half with the upcoming launch of the Roadster and the development of the future WhiteStar and BlueStar, Martin Eberhard wants to focus on a successful launch and further development of his baby. Meanwhile Michael Marks has experience running a $19 billion company and has agreed to step in until a suitable permanent CEO can be found. Right now all is still well at Tesla, if hectic, and Martin's move is not a sign of trouble.
[Editor's note: Tesla's Elon Musk has put out an official statement on the CEO switch, which you can read here.]
[Source: Tesla Motors]