Mike Langlois explains "How to Get Taken Seriously as a Mental Health Professional" in a mild rant about the uses and misuses of LinkedIn, etc. at http://gamertherapist.com/blog/2012/08/08/how-to-get-taken-seriously-as-a-mental-health-professional/
I get a referral a day from my website and many consultees from this blog. I tell other therapists, "If you want any clients under 65 years old, make sure that people can find you online.
I follow Mike on Google+. If you are an online-gamer or have clients who are gamers, you must follow him. I don't play online games, but do treat people who do. It's nice to have a clue about their experiences.