Primarily, I'd say it's application software support on Windows. Games? You get a few working under Wine, sometimes, partly, but they're far more likely to work well under the version of Windows they were tested with. Photo editing? Photoshop, or even Corel PhotoPaint, leave Linux in the dust. Video editing software? Nothing on Linux comes close to Vegas Video in features and usability. 3d Graphics? A slew of high-end solutions on Windows; Blender is nice on Linux, but has an exceedingly steep learning curve. There's a reason the original company went out of business. And as much as I want to like OpenOffice (and I do use it instead of Microsoft Office), it's too clunky compared to Office for me to recommend to non-geeks in good faith.

And, for developers, there's a market to sell applications to. When's the last time you saw someone making a living selling software to Linux consumers? (Web based products are an important exception to this rule, of course, but not everything can work well from a browser.) And as a bonus developers get to use the best IDE available anywhere.

These are just the needs I've had, for which I've actively looked for software on Linux to fill. Every single time the software available has been pathetic compared to the professional offering.

It's hard work getting that final level of polish on a piece of software that brings it from "it kinda works" to "it works really well." That's what's typically missing from open source apps: The push to make something really easy to use and solid. Frankly not enough professional applications reach that stage, but the ones I mention above all do.

Firefox is one of the few apps in the open source community to really reach that level of polish. Google Chrome is another. Thunderbird is another. There are a dozen other free programs I use, but none of them really feels polished -- they're good enough to get the job done, but only just. And if more things happen "in the cloud," that may be all people need in the future.

But until "the cloud" is brought to my house on fiber at gigabit speeds, I'd like to keep doing my video editing on a local system, thank you. And until it's less expensive to get a WiMax or 4G or whatever-new-technology wireless connection, I'd like the computing to stay in my laptop as well.