Upvote because I want to see this discussion. Honestly, it seems to be a simple "If we get acquired we don't need to ask you for permission", but it does lean a little harsh.
I think though that if you're going to be storing say, customer CC info, you don't want to be using a service like dropbox regardless of their policies. I don't think they are the right choice - you should be handling the security of this information yourself, or use clauses like dropbox's yourself to remove liability.
As a business, this would be the more worrying clause though:
We may employ third party companies and individuals to facilitate our service, to provide the service on our behalf, to perform Site-related services (including but not limited to data storage, maintenance services, database management, web analytics, payment processing, and improvement of the Site’s features) or to assist us in analyzing how our Site and service are used. These third parties have access to your Personal Information only for purposes of performing these tasks on our behalf.
Why? Because lord knows where the heck your information is, and if some admin from a company three steps removed gets his laptop stolen, it could come back to haunt you.