"Resource" is massively overused and misused.

Changing in many places to "response", since that is what HTTP caches work with. Avoiding
"representation" since some consider it a religious term (even though it is the correct one).
Tweak language
"private" is not necessary here, and may confuse.
Correct the semantics of "public."

There seems to be a cargo cult mentality around sending this directive; as has been discussed many times, "public" is usually not necessary.

See also:
  https://code.google.com/p/page-speed/issues/detail?id=9
Merge pull request #90 from mnot/cache-tweak

Cache tweak