If you use an alternative web browser on Windows 7, or use multiple browsers like I do, you know there's a game that needs to be played where each browser will continually prompt you about it not being the default browser. And you can choose to make that browser the default or tell it to stop bothering you. (In IE 9, this latter option is inconveniently hidden, but there.)
This is changing a bit in Windows 8, which I noticed when a hyperlink I clicked on in a Windows Live Messenger chat window opened in, of all things, the Metro version of Internet Explorer 10. Huh? I had previously configured Google Chrome as my default web browser.
Turns out Windows 8 actually uses that Default Programs UI more fully than did previous Windows versions, and now IE doesn't even include a switch in Internet Options to make it the default. Instead, you must go through Default Programs.
To understand what I mean, take a look at the top of the Programs tab in Internet Explorer 9 on Windows 7. Here, you see a handy button for making IE the default browser along with an option to warn you if some other browser tries to usurp its place.
In Internet Explorer 10 on Windows 8, this has changed. Now, there's a File associations area with a Set associations button that brings you to the global Default Programs interface.
One question I have is why Google Chrome didn't correctly assume control as the default browser. On that, I'm not sure. It's possible, however, that Chrome doesn't fully support every single file association that's available in Windows 8 (yet). So it could have grabbed the .htm, .html, and similar extension associations, but not the one used by Messenger for a hyperlink. Look how convoluted this is. How is a normal person supposed to understand this stuff?
Fortunately, you don't have to really worry about this. To simply make Google Chrome (or whatever) your default browser in Windows 8 today, you just need to go to Default Programs, click Set your default programs, and then select Google Chrome (or whatever) from the list of programs. Then, click the link titled Set this program as default.
And sure enough, those Messenger hyperlinks now open in Google Chrome like I wanted.
There are further questions here, of course. The most obvious concerns the interaction between IE 10 Metro and IE 10 "classic," and where and when each is used. I suspect these things will change between now and RTM, so I don't want to dwell on it too much for the Developer Preview. But the whole thing is rather curious, and I'll be looking at this more closely in the Beta build.