It's just the latest thing to be demonized. If it's not some kind of toy, or some game, it's something on the Net. But it's always something. My guess is that most jws will simply ignore it or rationalize it away.
That said, it can be a time-consumer. If you have a lot of friends and you get their news feeds, you can spend hours on the thing, which I'm sure worries the WTS/elders. Add to that the potential for contact with apostates, this high-control group might have something to worry about.