I've always wanted to mention Quake 2 on here, so here goes.

One of the big advantages .NET brought to desktop applications, at least in regards to official Microsoft dogma, was XCopy deployments: Instead of long, convoluted setups installing dozens of components into the system, shared libraries into system folders, and registry settings in the registry (and maybe some win.ini settings for real historical fun), XCopy allows you to build applications that can be "installed" by simply copying a folder.

Everything old is new again. Years back this was the DOS way, and in many cases it's still the UNIX way.

Some time back my favourite game on the Windows platform -- I did, and though the time is extraordinarily rare still do, play "shooter" games -- was Quake2, in particular with the ActionQuake mod. This game lived in my computing ecosystem for quite a while, not only because it was great fun, but also because the application existed as a directory "island" of sorts: John Carmack and crew had disregarded the Windows developer guidelines, ignoring centralized libraries, components, and registry settings, and stored settings in little config files in the application directory, with mods, extensions and libraries appeared in that directory or subdirectories.

I could "install" the application on a new machine, including all of my settings and extensions, just by copying the Quake2 directory to the new PC. Similarly, if I installed a new harddrive I could move it there and it was fully functional immediately. No complaints about missing libraries, or ridiculous dependencies upon fixed drive letters or fixed paths.

It just worked, and happily adapted to wherever it found itself.

This seemingly trivial "feature" made this application live on my hard drive far longer than it would have otherwise. Without the hassle of reinstalling the app everytime I upgraded machines or reinstalled the OS --  a nuisance that led to many apps getting left behind -- which would also have meant reinstalling all of the patches and mods, and then laborious reconfiguring the settings to a close proximity of my tastes, it just migrated with me. It was always there waiting to provide a quick diversion during a time of thought.

With XCopy deployment, Microsoft has shown that they've seen the light, and have realized that the whole "tentacles throughout the system" approach has been a terrible mistake.

With IIS 7 we might finally see the same sort of benefit for web applications. As it is IIS is a bit of a mixed-up configuration mess, with many directory-specific settings being stored in the IIS metabase existing somewhere else (on Windows 2003 it's a convenient, well-documented XML file that you can find at %sysdir%\\inetsrv\\metabase.xml) -- mime types, directory and file security, where virtual directories/web apps start, cache settings, etc. With IIS you can't simply XCopy the app and have full configuration, but instead you have to have appropriate permissions (generally administratrive) to open the IIS administrative console and set, for instance, that your CSS files should be cacheable for a day but the frequently rewritten XML file shouldn't be cached all, which tells IIS to add the appropriate HTTP headers to each.

Compare this to Apache, which lets you configure the vast majority of directory and file specific settings via .htaccess files in each directory, saving the "system wide" httpd.conf for settings that are truly web server wide. Configuration is logical and single point, and an application can be migrated with virtually all related setup with tremendous ease. A remote developer with access to only his folder of the web app has the ability to configure things as they should be configured without ridiculously requiring administrative rights.

IIS 7 adds this sort of functionality, moving a lot of the virtual directory and folder/file settings into files that you put in your web app file structure (obviously it won't, or rather won't under ideal conditions, allow these files to be read by web users). No more hydra-setup where half the setup exists over there and half exists over here.

Everything old is new again.