“We heard that the most common way you test across browsers is through virtualization of browser and operating system combinations using your favorite virtualization platform, such as Hyper-V, VMWare, VirtualBox, or Parallels,” Singhal wrote
True, and because of that the Microsoft website designer Expression Web 4 includes a program called SuperPreview (download link).
What this program does is take several webbrowser engines and renders the page you're working on using those engines. It supports several versions of Microsoft's Internet Explorer (obviously) but also FireFox as well as Safari. The best part is that it can display the same page, but rendered by different engines, side by side and even indicate problem areas. You can read more about this program on it's MSDN page
Yet guess what? This program gets dumped (it already lacked quite severely with regards to supporting modern browsers) together with Expression Web itself. There is also no comment (to my knowledge anyway) that it will surface again together with Visual Studio (which is the destined replacement for Expression web).
So please excuse me for stating that I consider this move quite hypocrite to say the least. You already had an awesome tool, which not only could clearly display changes and differences, it could all be done on one single developers workstation. No need for virtualisation, VMWare, Hyper-V at all.
You only needed to have the appropriate browser engines installed.
Then again; this is Microsoft we're dealing with and they have a tendency to simply drop good working software on a snap.