Microsoft has had an Anti-Spyware tool available (in Beta), for some time now.

There are two big problems with this:
(1) The average user trusts Microsoft - that is, they feel that if all they install is Microsoft products, and if the keep Windows updated, they will be safe. (Actually, this is probably the slightly-above-average user; I wonder if the average user even thinks this much about PC security).

(2) The big problem is that Microsoft has absolutely zero credibility when it comes to spyware. They may have a nice writeup on Spyware analysis, but it is the results that matter. And there, Microsoft AntiSpyware fails horribly, and - even worse - intentionally.

You can see from the screenshot of the MS “advanced spyware quiz”, part of the deception MS is engaged in - the letter in Response to questions about Claria (Gator), a company so reviled and notorious for spyware, they changed thier name (Gator). This is a company so reviled, that it has made other companies consider changing their names because it had “Gator” in it. That’s pretty strong stuff right there.

I would say the Claria (Gator) thing is understandable from the perspective that MS is/was in talks to buy Claria - and it does seem a bit odd for MS to straight up recommend deleting a product that they are trying to acquire. (I leave the obvious commentary on why they would want to buy such crap in the first place to the reader’s imagination.)

The bottom line: You can not trust Microsoft AntiSpyware to do the right thing. Period.