IT departments love control and for a good reason. Security is a major concern for large corporations with thousands of employees, but even a small business like your local bakery also wants to be protected from cyber crimes.
The challenge is a lot of people are switching to a new breed of web applications like dropbox and box.net which are very easy to use. Employees already use these tools at home for their everyday lives and they love it, so why not at work!
The problem is security and lack of control over these application. IT departments need the ability to tackle issues and attacks in real time and depending on a service such as Dropbox might not be their ideal solution.
Dropbox and other services are noticing the trend and started offering business packages and more control for teams.
To me the main thing to understand here, is the power of good design and development. People use applications like Dropbox because they are so easy to use and there are no crazy setup preferences to make you call a younger son or daughter to teach you how to do something.