News Analysis. Apple Software Update is the Mac maker's back door to the Windows desktop.

Earlier today, Apple released the Safari 3.1 Web browser for Mac OS and Windows XP/Vista. A couple hours later, Apple Software Update popped up on my daughter's Sony VAIO, offering Safari 3.1 for download. I didn't recall seeing an earlier version installed on the laptop. And I made no mistake: The Apple updater offered installation of new software, not something that had been there before. Whoa.

Apple distributes its software updater with iTunes. Adobe is among the other developers that also distribute software updaters with some products. But Apple has taken an interesting approach: using its updater as a Trojan horse for promoting software not already installed on the Windows PC.

Apple's approach is atypical. For example, I use Internet Explorer and Mozilla Firefox on my Vista PC. Mozilla's software updater automatically downloads Firefox updates, but it doesn't prompt me to download Thunderbird, which isn't on the laptop.

Already, Apple uses iTunes as a mechanism for distributing QuickTime. One requires the other. The updater isn't a required install with iTunes, and it can later be removed. But the strategy of using the updater to deliver other Apple software is an aggressive encroachment into the Windows desktop. It's smart business, but is it good for enterprises?

There are reasons why IT organizations use tools like WSUS (Windows Server Update Services) to control and manage software updates. But what about rogue updaters that come with products like Adobe Reader, Firefox or iTunes? Policies can be set to restrict new software installation, but not every IT organization uses them. And where should that line be drawn? It's one thing to let employees install iTunes and something else for Apple Software Update to offer another Web browser.

Enterprises should be concerned about rogue browser installations, for reasons I shouldn't have to state. Safari is fairly new to Windows and has yet to really show that it has can muster the security to withstand the associated attacks. Mac OS X is a quaint neighborhood where little Safari was safe. By comparison, Windows is a gang-ridden ghetto: life is survival, and it's tough going.

Apple has plenty of reasons for pushing out Safari to Windows users:

* Google is Safari's default search provider, and Google pays. There's good money to be made in search.
* Apple's iTunes software uses Safari as the browsing engine.
* There are hidden PC-to-iPhone and iPod Touch synchronization benefits and obvious iPhone SDK benefits with Safari on the computer.
* Additional software further propagates the Apple brand.
* Apple one-ups Microsoft with a presumably more standards-compliant browser than the Internet Explorer 8 beta.

I'll selectively call out the last point. Microsoft brags about improved CSS support and limited HTML 5 support in IE 8, which won't likely be released until next year (yeah, that's the timing I got from Microsoft). Apple claims support for CSS animations, HTML 5 multimedia and Web fonts. Today. Not someday. And it's available without asking.

Microsoft talks about software plus services. Looks to me like Apple is using a service to push software deep into Microsoft-controlled territory. Enterprises should worry about other developers adopting this kind of practice. But as a competitive tactic, Apple is wisely leveraging its limited resources.