A nemesis can be useful: without the Joker, Batman is a rich nutcase with a taste for spandex. Google too needs a highly visible enemy to distract from its dominance of online search advertising as it moves into other markets such as selling digital books. Microsoft, taking over search mechanics at Yahoo, is the prime candidate. But the software company might better challenge Google by giving up entirely.
After all, Microsoft's online business is a money pit, losing $4bn during the past five years. Arguably the greater threat to Microsoft are free alternatives to its software and Windows operating system being developed at Google, a company awash with cash from its golden goose of search. Stepping away would leave Google with a natural monopoly, daring governments to step in and limit returns and behaviour as with railroads, utilities and phone companies in the past.
The chances of Microsoft acquiescing are slim. But it highlights one of the most important jobs for Google management: to prolong as far as possible the period during which it remains uninhibited, and so able to make very high margins and returns.