Google accuses Microsoft of anti-competitive behaviour, in that Vista currently leverages its own desktop search over Google Desktop and other alternatives. This issue is well-covered elsewhere, but some thoughts come to mind...
I'm seeing a lot of black pots and kettles here.
More to the point: If an alternate serach is chosen by the user or system builder, is the built-in Microsoft indexer stripped out? This article suggests it won't be.
That's the ball to watch, because so far, Microsoft's approach to enabling competing subsystems has been to redirect UI to point to the 3rd-party replacement, without removing the integrated Microsoft alternative.
That means the code bloat and exploitability risks of the Microsoft stuff remains, and that in turn makes it impossible for competitors to reduce the overall "cost" of that functionality (as using something else still incurs the "cost" of the Microsoft subsystem as well).
This is particularly onerous when the Microsoft subsystem is still running underfoot.
For an example of the sort of problems that can arise; if you have an edition of Vista that does not offer the "Previous Versions" feature, you still have that code running underfoot, maintaining previous versions of your data files. If someone subsequently upgrades Vista to an edition that does include "Previous Versions", then they can recover "previous versions" of your data files, even though those files were altered before Vista was upgraded.
So it's not enough to give Google (and presumably others, this complaint is not just for the benefit of the search king, is it?) equal or pre-eminant UI space. If one has to accept the runtime overhead of some 3rd-party's indexer, then it's imperitive that Microsoft's indexer is not left running as well.
As it is, indexer overhead is a big performance complaint with Vista. If 3rd-party desktop search has to suffer the overhead of two different indexers, the dice are still loaded against the competition, because no matter how much more efficient the 3rd-party indexer may be, the overall result is worse performance.