Here's what they have to say for themselves: "Welcome to the web’s first and still best self-help resource for those with anxiety disorders. Panic attacks, phobias, extreme shyness, obsessive-compulsive behaviors, and generalized anxiety disrupt the lives of an estimated 15% of the population. tAPir is a free grass-roots website dedicated to providing information, relief, and support for those recovering from debilitating anxiety."
I have only just started dipping into the site but it looks pretty good to me. There is a fairly high incidence of these problems in the general population. It's inevitable that we will meet people with these difficulties amongst our clients (and colleagues).