I have looked around my neighborhood, and I detect no Terror at this time. If the object of the articles was to produce Terror by threat alone, it seems the population has grown deaf to threats.
I don't think it is intended to produce terror. I would be more cautious to read these as preliminary actions by seemingly disparate groups to redirect attention in the event a significant event occured in the near future. If something significant occurs, the already posted warnings would serve to distract resources from identifying a real threat or organized effort to create a maneuverable environment.
IMHO, I'd start tracking socialist leaning groups and their communications, now in order to discern who might be behind something more significant.