Browsing the Web on Windows 8
Windows 8 ships with Internet Explorer 10, albeit in two editions: a conventional desktop version and a Metro-only version. The differences are more than cosmetic: They're incarnations of Microsoft's philosophy of how Web browsers should behave in Windows from now on.
When the first test releases of Windows 8 became public, people winced at how the Metro version of Internet Explorer 10 (the default version of IE bundled with Win8) didn't support Flash, due to tightened rules about how IE in Metro supported third-party add-ons. The short version: It wouldn't. If you wanted to use a browser plug-in with IE, you had to use the desktop version of IE.
The prerelease versions of Windows 8 backtracked slightly on that stricture, by using a workaround that should be familiar to users of Google Chrome. Flash's functionality is baked directly into Metro IE, rather than included as an add-on. To that end, Windows 7 users who do any work with IE can stick with the desktop version for the full gamut of functionality, but they can also load a page in the Metro version without worrying about losing the functionality of the most commonly used third-party browser component (save perhaps for Java).
Internet Explorer 10 for Metro gets around its own no-third-party-plug-ins restriction by baking Flash functionality directly into the program.
Things get a little sticky if you want to use a browser other than IE in Metro, however. Microsoft has restrictions about Metro apps that perform Web browsing. By default, those apps are encouraged to use the IE engine, for the sake of keeping the performance and security of those apps consistent with other Metro apps. That said, an app that is primarily a legacy-desktop app can implement a Metro "facet" for that app, as long as the app in question is installed as the system default browser.
Google Chrome already supports this behavior, although right now the Metro edition of Chrome is little more than the desktop version running full-screen. Expect future editions of Chrome to have closer Metro integration -- for example, with charms. Firefox users, however, will have to wait a bit, as Mozilla is planning a full Metro-themed UX overhaul for its browser. Opera is rumored to be doing something similar.
Chrome's "Metro edition" is actually Chrome itself running in a full-screen incarnation.