It doesn't really matter whether Snowden released NEW information about the extent of US surveillance. (I think he did, but I'm not going to get into a pissing match to prove it.)
Personally, I didn't know anything about the extent of it, but I have generally been aware of the potential for my electronic communications to be stored & monitored, & have tried to conduct myself accordingly. I don't think I'm unique in that regard.
The important point to my mind is that in the Before-Snowden era, nobody was talking about it; a lot of people were either in denial or cognitive oblivion about the nature and extent of government intrusion and spying in our daily lives.
Now, Post-Snowden, we are paying attention. Politicians from the far right like (ick!) Sensenbrenner to the middle-left like Wyden (there is no far left) are up & screaming.
Our allies, fearful of their own citizens, are hypocritically jumping down our throats about it (never mind their own surveillance programs or their collaboration with us). The hypocrisy is of far less import than the amazing international scope of the brouhaha.
For anyone who values freedom, who deplores secret courts using secret means to secretly authorize secret surveillance activities, Snowden and his associates have been a potential game-changer. And it matters not a whit if they are heroes or villains. The fact is that we are all now talking about a whole pile of corruption that had previously been hidden from sight, secretly festering at the core of our rights as citizens of the world.
In the past, a few of us have been aware, to some degree, of many very bad things that we were unable to alert the public at large to. Nobody would pay attention. Now, Post-Snowden, the public at large has at last awakened to one element of the worldwide power-grab that the Masters of the Universe, and their government lackeys, are in the process of enacting.
For that, we are in debt to Snowden and his supporters.