Microsoft, Google, Facebook and Yahoo have no incentive to show their middle finger to the government.
As soon as your company receive a subpoena (or even a "national security letter" for that matter) from the government to hand over your users' data, the size of your company or your business model does not matter at all.
Don't hold your breath for Microsoft, Yahoo and Google to fight for your rights. The same goes for Dropbox. That is why suggesting to move from Dropbox to Microsoft/Google Drive does not make any sense.
As soon as your company receive a subpoena (or even a "national security letter" for that matter) from the government to hand over your users' data, the size of your company or your business model does not matter at all.
Don't hold your breath for Microsoft, Yahoo and Google to fight for your rights. The same goes for Dropbox. That is why suggesting to move from Dropbox to Microsoft/Google Drive does not make any sense.