I prefer not knowing too much about my therapist's personal life. It's none of my business, and quite frankly I don't want to know unless he chooses to tell me things - and usually I'm glad that he doesn't.

However, I did google both my exT and my current T before meeting with them for the first time. It's the only way to find out about their professional background, except for asking them, which can't be done before the first meeting! With exT, I read an interview with her on a blog about psychotherapy, and with current T, I read a few articles he has published.