I'm not a member at the moment but I was when I was looking for jobs. It saved me from accepting a position at what sounds like a hellish school in the Middle East going from the reviews and what I found out through other sources.
I believe you can join as a parent as there are some parent reviews on there. In particular about a certain school in Bali that has been mentioned here a few times. It's also useful to find out how administrators are viewed not just at their present school but at previous schools. I should add that some of the reviews should be taken with a pinch of salt as some are from disgruntled employees and other aren't so much comments about the school but the culture or the place the school is in.
There are quite a few Jakarta schools and other Indonesian international schools listed. Some make for interesting reading. You can read the reviews from as far back as they were written.