As long as you aren't using a service with your actual data.
If I use Tor to connect to facebook and input my personal information, Tor is only protecting my data in transit. The NSA can still request the data from my account from facebook.
With a Tor hidden service, the NSA cannot necessarily find the service provider. Of course, neither can I, so there is a whole different set of threats (and it could be the NSA providing the service in the first place) but it does help a little with this specific problem.