I think that popular causes with centralized leadership typically have a mix of grassroots and astroturf support; the question is how much support is of which type. For Slashdot, or the Tea Party movement, or the Daily Kos, my guess is that the grassroots-to-astroturf ratio is _very_ high in favor of grass. I would be surprised if Russia doesn't employ a lot of astroturfing, but they also enjoy a lot of support from their population -- cf. http://www.slate.com/id/2197514/, and I've heard the rumor that Vladimir Putin is the only force keeping Russia from going Neo-Nazi.
China, though, probably has a lot more astroturf than grass. I've had trouble determining how much of the passionate defense of China on the Internet is real (with the same mentality as the defenses of the late 1800s and early 1900s, probably -- a somewhat grating but thoroughly justifiable one), and how much is less than real... it looks like most of it, or at least most defense of the PRC government, is in the latter category. You don't see crowdsourced counterattacks and a memetic "Ode to a Grass Mud Horse" when the opposition is small.
China, though, probably has a lot more astroturf than grass. I've had trouble determining how much of the passionate defense of China on the Internet is real (with the same mentality as the defenses of the late 1800s and early 1900s, probably -- a somewhat grating but thoroughly justifiable one), and how much is less than real... it looks like most of it, or at least most defense of the PRC government, is in the latter category. You don't see crowdsourced counterattacks and a memetic "Ode to a Grass Mud Horse" when the opposition is small.