Maybe the signal is just whatever they know and think is important. When you hold your own beliefs and opinions in higher regard than anyone else's, it's apt to call anything you approve of "signal."

It could also be just a meme term that draws engagement. But à la Syndrome, when everything is signal, nothing is.

And then you have people who present the real signal, and it's ridiculed, attacked, and subsequently ignored. So that's what I look out for.