"Free" isn't the thing Microsoft should be worried about. If Twitter grows to become 50,000 people in 10 years, they won't select Google Docs because it's free.

"Free" isn't the thing Microsoft should be worried about. If Twitter grows to become 50,000 people in 10 years, they won't select Google Docs because it's free. They'll choose it because it helps them get work done better for an overall lower cost, and that is really what Microsoft should be worried about because their competitive edge in most areas is eroding quickly. For example, Android isn't going to beat Windows Mobile because it's free. It's going to beat Windows Mobile because it's really a better OS (i.e. it's relatively open, has more apps, improving rapidly, etc.)