When I heard the Safari-for-Windows rumor, my response was, "It'll never happen -- Apple is a hardware company." Apple's business model is: (1) make objects; (2) sell them for a profit. They make OSX to sell Macs. They make iTunes (for Mac and PC) to sell iPods. How could Safari for Windows help their bottom line? If I had had more time yesterday I would have written a post to that effect, linked to Mary Jo Foley's blog, and looked like a moron.
So now I'm confused.
The main justification I've heard is that WinSafari is a kind of advertisement for OSX. As Engadget put it, "it seems the Apple folks plan to use it in much the same way they've used iTunes to grow the Mac fanbase by giving Windows users 'a glass of ice water to somebody in hell!'" In other words, Steve Jobs believes that PC users will try Safari and think, "This free browser is awesome -- now I'm going to spend $2,000 on a new computer to get other software that is presumably equally awesome." I find this hard to believe. Safari is a good browser, but it's not that much better than Firefox.
So what's Apple thinking?
My guess is that it has something to do with the new iPhone development standards that Jobs announced today. For those of you who don't follow this stuff as obsessively as I do: independent software developers (i.e. programmers who don't work for Apple) will be able to write programs for the iPhone, but those programs will be akin to "web apps" like Google Maps and Flickr -- they'll run in the iPhone's web browser, which (it so happens) is a version of Safari.
So what I'm thinking is this: there will be occasions when a developer wants to write a program that runs on both the iPhone and the desktop (e.g. a program that syncs data between your phone and your computer in some specialized way). For most purposes, the iPhone will integrate with your computer using iTunes, just like the iPod does. But these new iPhone programs can't run in iTunes, because iTunes doesn't run web apps.
If Apple wants to accomodate them, there's three choices: (a) build browser-type features into iTunes; (b) force developers to write apps that work on Firefox or Internet Explorer as well as Safari; (c) port Safari to Windows. Option (a) stretches the iTunes concept (already pretty elastic) past breaking point. Option (b) would have worked for a while, mostly, but it risks sticking developers with compatibility issues going forward, which might have been a brake on iPhone software development. Option (c) allows Apple to build special features into this or future versions of Safari, just for developers of iPhone software.
So that's my guess: that the version of Safari on your computer will integrate with the version on your iPhone in some way. Time will tell.