True things. It's hard for me to explain to my parents how things work now. They don't have the concepts, and they CAN'T because they can't have the same formative social experiences.
i think there's a difference between slacktivism hashtags (#Kony2012) vs ones that actually drive forward the public discourse (#BlackLivesMatter). The "things" which hashtags refer to have always existed in pop culture, but now we have a social means of labeling them explicitly.
It's more than that. It's the expectation that you have to expend a certain amount of effort, money, time, or other resource to be allowed to consider yourself an activist, or your opinion valid. Your working poor individual with two minimum wage jobs still consumes media and has valid opinions, but none of these resources to spare. All they can afford to do is "slacktivism" and it's not because they're slack. Dismissing hashtags movements, even ones like #Kony2012, as slack or lazy is literally dismissing the voices who cannot meet a certain arbitrary investment criteria. Fuck that noise.
I really like this analogy. Usually when I make analogies to "signal-noise ratio", I'm thinking of comprehensibility (or lack thereof). But that usually only applies to one speaker/author/whatever. Your analogy is referring to something that's abstracted over individuals, something that's closer to how political ideas spread.