Doc
The beaches you mentioned are far from a secret. That being said, there is only so much real estate to fish from on most beaches.
It is a bit different story if you have access to a boat.

I personally don't name beaches regardless of how well known they are.
That is out of respect for the locals and old timers that have fished there long before myself and helped teach me the beach game.
Simply naming the MA area you are fishing rather then specific beaches certainly helps eliminate crowding.
If you like crowds, keep naming beaches. Just don't bitch when your favorite beach get overly crowded.
SF