Microsoft is making a conscious effort to push the task of site administration out of the realm of IT administrator. Organizations can be decentralized and become agile if the ability to do more comes closer to the front lines. Yet, organizations still need to retain central control and ensure the integrity of their SharePoint Farm solutions.
The Sandbox functionality in SharePoint 2010 is an example of a win-win solution. IT retains central control of the farm, the hardware, and provides limits. IT administrators can designate a power user who has the ability to roll out code for their SharePoint instance, without adversely affecting the entire farm.
Many modifications can be done at the site collection level by power users. These modifications have ramifications across the entire organization. Here is a simple clarification of the terms site and site collection: