Finding software in Ubuntu Linux is a pretty painless task. There are basically two main ways people do it (with a few others that are harder and seldom used): through the new Software Center or through the Synaptic Package Manager. Whether users choose to use the Software Center or Synaptic, finding and installing software is as painless as clicking the program, searching for a term, and double clicking to install. Uninstalling is just as easy.
The same process on Microsoft Windows, by comparison, can be much more complex. Users have an infinite amount of sources for software from retail outlets to niche online stores, competing download sites, and even personal sites where software created by the site owner is hosted for download. Sometimes, just finding the software is more than half the battle, then there's installing and uninstalling it which can be an even bigger pain in the ass.
This problem doesn't just plague Windows though. Mac has had the same problem for a long time until, recently, Apple decided to do something about it by opening a desktop app store similar to the one they run for the iPhone and iPad devices. Brilliant idea! Allow users an infinite choice of free and paid software applications, but consolidate their location from multiple sites down to a single one. Regardless of what you might think of Steve Jobs and his need for iron fisted, white knuckled, control of Apple users, the idea of having a single place to go for all your software is very attractive. Ubuntu is seeing huge success with the Software Center and Apple has seen an extremely positive response to their announcement of an desktop app store.
Where is Microsoft? Why are they not feverishly working on a similar thing for Windows users? Not only is an in OS app store a great win for the user experience, but it's a fantastic way for a company to generate additional revenue by taking a cut of every app sold in the marketplace. Microsoft has seen solid success with the Windows Phone Marketplace; why have they not extended the technology to the desktop? It would be very easy. Just add it to Windows 7 as an additional program or even integrate it with the built in search functionality. It's something that could be deployed in a matter of weeks and Microsoft could easily leverage existing technology to make this a stellar experience for Windows users.
An in-OS app store makes sense from any angle you look at it: users win, developers win, Microsoft wins, everyone is happy. There's no compelling reason for the company not to jump on this idea like a hungry dog running to a bowl of fresh food. This is their chance to be innovative, to be an aggressive mover in the user space, to really push the user experience forward.
If they wait much longer, it won't matter. Everyone else will have an app store and, once again, Microsoft will show up late to the party with their homely cousin Betty as their date.