In a comment on another post, Thomas Brock asks:
So… Will these additions to AV services, the anti-spyware services, the media playsforsure services and the internet and desktop search services add to the monopoly charges?
Short answer: No. Everything Microsoft does with Windows has to be cleared by the Department of Justice. That was one of the terms of the original antitrust settlement. Reasonable (and not-so-reasonable) people may disagree over how fair that settlement was, but the DOJ holds the cards and they get veto power over lots of decisions. You can also be certain that any decision to add a feature has already been reviewed by a room full of lawyers.
My personal opinion is that security features belong in the operating system. Internet connectivity and Web browsing tools are an essential part of any computer operating system today. Forcing Microsoft to maintain an environment where users must purchase add-on products so that they can safely use core features of the operating system is just wrong.
Search capability belongs in the OS as well. In fact, it’s always been there; it just hasn’t been implemented well. If other people can do it better, more power to them. That’s been the model so far for alternative browsers, and it seems to be working just fine. Firefox has been downloaded 25 million times, mostly by people using Internet Explorer. There’s nothing in Windows that keeps me from downloading, installing, or using Firefox. This is a great example of a product that does a better job than Windows and is deservedly reaping success.
Update: Symantec’s CEO, John Thompson, seems to agree, according to these remarks from yesterday’s RSA conference, as published in the seattlepi.com Microsoft Blog:
On whether Symantec would raise antitrust objections over Microsoft’s decision to offer free anti-spyware protection to Windows users: “I’d rather fight Microsoft in the marketplace because we’re convinced we can whup ’em. So this is not about showing up in Washington or whining on someone’s doorstep about what Microsoft can or might do. To the extent that they violate the position of prominence that they have, be assured that we’ll be watching, but whining in Washington about press releases or pointing to left field by Bill and his team, I mean, of what value is that?”
Not to mention that the complaint would go nowhere.
Ed Bott 
I like Symantec’s attitude, but I am not so confident that Microsoft will be immune from antitrust pressure even if the Justice Department decides to allow the add-ons. As far as I know, the government’s decision would not be binding on private litgants such as McAfee, Trend Micro, Computer Associates, Symantec, etc. Besides, if the Microsoft free antivirus software is good enough — and it will be, even if other vendors promise additional features — why would the average user want the additional bells and whistles of these third party antivirus programs?
Having said that, I couldn’t agree more that security software should be a standard part of Windows. As a user, the one thing I can expect is that Microsoft security software will work with a Microsoft OS in a way that strikes a reasonable balance between performance, stability, and security. Most third party vendors — did someone mention Symantec? — seem to be all too willing to sacrifice performance and even stability to get a bit more security beyond “already good enough.” Security is great, but if it is already good enough, I don’t want to sacrifice performance or stability to get a bit more security.
Ken
Well, I’m not a lawyer, but if I recall correctly the gist of the complaint against Microsoft was that their “middleware” products were anti-competitive. The definition of middleware included the possibility that a competing product could conceivably become an “alternate platform” to Microsoft. Thus Internet Explorer, the Java Virtual Machine, and Windows Media Player (to name just a few examples) are middleware because they enable new capabilities and can become platforms for entire businesses. Security software may be a large business, but it isn’t middleware, and it certainly isn’t a platform because it doesn’t enable expansion.
Good for John Thompson. Don’t forget that historically, Microsoft products especially add-ons and middleware have often not been the best in the market, but “good enough.” Symantec can continue to compete as long as they build a better product (or are perceived to). Even Google’s software isn’t the best in the market, but that doesn’t prevent a large majority of people from using it.
I agree that there will always be a market for vendors, such as Symantec, who offer software that they claim does something that Microsoft software doesn’t do, or does something that Microsoft does do, but better. The question is whether they can compete once Microsoft begins giving away for free software that for years has been the domain of third party vendors (e.g. antivirus software). If not, you can safely bet the ranch and your first born that someone will sue Microsoft.