alt Hacker NewsI would bet money almost no public meme groups are monitored by any intelligence agencies. And the few that are mostly only are just in the sense of being casually co-opted by state-sponsored trolls with almost no attention from actual intelligence agency staff (in the way this thread implies, with investigations and deanonymization and such).
I'm sure they're "monitored by intelligence agencies" in the sense of having a line in a database/report somewhere (that probably no-one reads). If the technique mentioned in TFA can be used automatically (and I see no reason it shouldn't) then it will probably be incorporated in due course (if it hasn't been already) - it doesn't have to be 100% accurate, it's just one more datapoint to add to the mix.