I have a simple request for everyone, as you surf the web and interact with other users: don't be a jerk.
On the surface, it seems like a simple request. We've been raised with this simple lesson, haven't we?
But, alas, when we feel our intelligence is being insulted or challenged, many of us feel we must retaliate. This is the worst thing we could possibly do. If someone is trolling, they don't care how much evidence we have to support our case. If someone repeatedly refutes our evidence by pulling rank ("I've been in this business for 20 years!"), cease and desist. We can't control how others conduct themselves on the internet or elsewhere, but we can control how we react to it. I remind myself of this often, but I have made the mistake of engaging when I shouldn't. It's a human mistake, so I hope the person on the other end of the line knows not to deal with me on a day in which I should not be within 50 miles of a keyboard.
Here is a chart that may help you identify a lost cause.
Sources: 22 Words and Atheism Resource.
Save yourself some agony and recognize when someone is not willing to change their position in light of solid data. Recognize when you've entered the realm of opinions and subjectivity. Though I don't have numbers to prove it, I have a feeling that most people live there. If you do make a permanent home there, please learn how to approach a dissenting opinion. Not everyone is going to agree with you in all things. You don't need to be in eternal agreement in order to have a good conversation.
Since so many people view a dissenting opinion as an automatic attack, my online involvement is limited. The only online forum for massage therapy that I'll engage is POEM | Project for Open Education in Massage, and I've given up on LinkedIn conversations. If we can't be decent to each other, it isn't worth the time or effort.