Natascha, welcome! I think PP is a great choice for people who are concerned about health first and foremost. Have you read the book (or books) yet?

Petra, paying is an option if you feel this site has benefitted you and you'd like to help out, not to mention get some more space for PMing or photos or whatever (keep in mind sometimes you want to keep records of the PMs and also write more than space allows, etc.). Mostly I think it's just about supporting (voluntarily) a place that has, for free, made a real impact in your life. I was here for awhile for free to check things out before I decided to contribute.