How can I enable convenient, secure access to Microsoft SharePoint?

The extremely rapid rate at which Microsoft SharePoint is being adopted and deployed by business constituents presents a number of challenges to IT security organizations. IT must strike a balance between providing users with easy access to the information they need and instituting the necessary controls to adequately reduce security risk. Compounding this challenge is the fact that SharePoint is heavily document-centric. Sensitive data can be stored in files which appear harmless on the surface yet are easily duplicated, shared or deleted outside the view of the security organization.