DISQUS

> Even if Google/Yahoo! were a monopoly - and I just
> don’t know how to gauge when that line is crossed - it
> wouldn’t matter.

The legal test for monopoly is monopoly power -- the power to exclude entry or raise price -- in a relevant product market. Goggle's high share of Intenet search advertising doesn't equate to anything close to monopoly power because (a) search advertising competese with display advertising, in which Yahoo! and Microsoft are far bigger, as well as, increasingly, traditional media advertising like newspapers and radio. Hence "Internet search advertising" is way too narrow to be a revelant market; and (b) Google has no technical or business ability to kep out rivals or raise prices. Unlike a Microsoft, for instance, Google has no interoperability entry barrier or even a "network effects" advantage; if other search platforms delivered more users/impressions for advertisers, those dollars would move instantaneously.

The only way Google stays ahead is by running faster than its rivals. That's the archetypical definition of a competitive firm, one without even a shred of market power.