Your operating system can run processes in the background -- things like realtime antivirus protection and streaming movies and music around your home -- and so can Google Chrome. Background apps have existed in Chrome and Chromium for some time, but now that the Chrome Web Store is open and its apps are available for installation, Google has posted a blog about why backgrounding is cool.
It's really all about Chrome being your "OS" even if you're using a Windows or Mac computer. With the ability to run Web apps in the background and Native Client support headed to the beta and stable channels in relatively short order, Chrome Web Apps will soon be capable of doing many of the same things your traditional desktop apps can do.
Google's post talks about using backgrounding to issue notifications (as apps like TweetDeck and exfm do) or to prefetch data. There's really no end to the possibilities, and we're exited to see what the next generation of Chrome Web Apps can really do.
Still, it's a bit more than I wanted. Give me a simple right-click, set-as-wallpaper option. And that's precisely what Mohamed Mansour has done. Witness: the Set image as wallpaper extension for Google Chrome! Right click, set image as wallpaper, and an HTML5 previewer appears so you can eyeball the finished product -- you can even choose to stretch, center, or tile your image. Future versions will include an options page that allows you to skip the previewer and simply perform a two-click image swap.
Unfortunately (or fortunately, depending on which OS you use) Mohamed's extension currently only works with Windows. Linux and Mac versions are being worked on.
By the way, there's absolutely no need to panic over MG Siegler's comments on TechCrunch that "someone fed the bloat trolls." Set as wallpaper only uses about 5MB memory -- the same as most other basic extensions. Clearly MG thinks that saving an image, locating it on disk, and then using OS X's built-in controls to set the wallpaper is a much more elegant way to do things.
As for me, I'll take my context menu enhancement, thanks.