I found this picture on the web and it captures the spirit of trolling: an ugly cuss who quite enjoys vile, who will use the politics of personal destruction early and often even when the topic is abstract and there are no personal issues in play. They collect information, twist it and then in short quick bursts piss in the punchbowl.
I call this fellow iDUBBY to remember how one handles him. With most social media platforms such as Facebook, there is an order of operations that will get rid of iDUBBYs when they invade your space.
Social media implies a responsibility to preserve your own reputation even if it means shutting up. It also implies a responsibility to be smart and non-reactive. Again, sometimes the person stayed too long at the nachos and dip bowl and then failed to slip outside for a smoke before moving on to the anchovies. Best to tolerate what is not too odoriferous or move next to the band where the noise drowns out the heavy sighs.