Or has this been happening already and I just missed it?
Like most of us do not go to protest on the streets over such a thing, most celebrities will not be bothered to stick their head out in a possibly career crippling way.
The ones that do regularly are quickly labelled as parts liberal Hollywood that can be disregarded.
Another thing is that actors are part of the big movie-industrial complex that has a lot of interest in surveillance because they perceive this as their only hope against the free distribution of data.
But I agree it would be worth the effort to actively pursue people like Matt Damon to give the cause widespread legitimacy. Easy it will be not, I'm afraid.
I sincerely welcome this; celebrities have large networks.
http://www.huffingtonpost.com/2013/07/18/jimmy-carter-edward...
It's still only middle ground, though. Once we can get One Direction involved...
I was thinking generally of famous people that don't have a past or present connection to public policy. Either way though, it's a grey term, so there is plenty of room for interpretation. The point, I think, remains the same.
As far as famous people of any sort talking to the public on this issue, my attitude is the more the better.
http://www.huffingtonpost.com/john-cusack/snowden-principle_...
It doesn't seem to have much more impact than when anyone else does it.
Not sure how one would measure that specifically, but any sort of public education on the issue by any influencer with a significant network is additive.
Maybe if celebrities bring it up in forums the larger public can't/won't ignore, their visibility would generate a larger reaction. (e.g. mentioning it at awards shows or live interviews or the like)