Let me ask you a simple question: How many versions of Microsoft Office do you currently have across your enterprise?

If your answer is more than one, or you don't know, or your users are running three different word processors, then maybe it is time to think about streaming your applications from a central place and trying to regain control here.

The idea is simple to understand. Just as you stream a video or music file to your desktop from across the Internet without actually making a copy of it to your hard disk, the same happens with your applications.

A streaming server sends all the information needed to run the application at the moment it is needed. Of course, you can use application streaming for more than just tracking down errant versions of Office, indeed, for any supported application.  But certainly, Office makes for a compelling case. Running multiple Web browser versions on the same PC is another one.

Why bother?

You don't consume individual client licenses for each streaming application. You save on desktop disk storage space and installation issues. And you regain some control over runaway version-itis, too, because your apps are always patched and current, and upgrades are trivial.

This has a lot of appeal for enterprises that want to simplify their security exposure. On top of all of this, users can work from a wide variety of desktops without having to worry if their apps are pre-installed, such as at an airport lounge or a coffee shop. As you roll out new applications, you can deploy them with centralized access controls to make them more manageable. 

There are three main companies in this space: Microsoft, through its purchase of Softgrid, Appstream.com, Thinstall.com, and the Altiris unit of Symantec with its Software Virtualization Service. Just to make matters worse, the three non-Microsoft vendors have a complex web of cross-licensing arrangements.

There are some downsides.

First, while the concept is simple, the actual execution is anything but. There are a lot of subtleties, such as figuring out the right "package" to stream down to each client, to make sure that everything that is needed by the application – DLLs, configuration files, drivers, and so forth – is in the package and in working order.

A streaming vendor also has to deal with application isolation, to make sure that it is protected from other applications that could step on it, or it on them, on the client system. And, the package needs to be optimized for the end user experience just like a streaming video, so that the app starts up in a reasonable amount of time and doesn't consume gobs of Internet bandwidth in the process of being streamed.

On top of this is integration of the package delivery with the vendor's own enterprise software distribution system, which is why both Microsoft and Altiris are in the game.  If you are already using SMS or some other desktop delivery service, it pays to take a closer look at how streaming can help.

Another drawback is that these products are still fairly new, and rough around the edges. Thinstall requires a Microsoft network share to deploy, so it won't work across the Internet without a VPN. And not all applications can be streamed, at least not just yet.

If your application requires access directly to the underlying operating system, or to specific services, it will not be streaming-friendly. To help these matters, the vendors have put together some developer tools such as Altiris' Juice and Microsoft's Desktop Optimization pack.