What open data is available about the number of visitors, type of browsers, etc. of U.S. Federal websites? Is there both historical and real-time web analytics data available to the public?
You can find some stats for individual sites by searching for the names of weblog analyzers that generate HTML reports and restrict by agency domain. For example:
The current administration lifted the restriction on 'sharing data with third parties' if there was some sort of a benefit ... so some agencies started using Google Analytics or similar.
Automatically Collected Information
This website uses Google Analytics Premium. ...
Providing Information to Third Parties
NASA may share information with private organizations as part of a service that provides NASA users with increased capabilities or functionality on the site.
I see nothing in their policy that forbids them from sharing data if there isn't a benefit, so it's possible that a FOIA request might be able to get access to it.