I use about three expat forums, but tbh they have got pretty boring with about six regular posters. They were useful when we first arrived and needed to know things, but now they seem to have a lot of boring threads and bad-tempered exchanges. I like Mumsnet; clearly I don't read or relate to all the threads, but I do find quite a lot of interest. There are, for example, far more posts on the book threads and I find out about new authors. It can be rude, aggressive and sweary, but also very caring and supportive. Best thing is that there are masses of people on it so you don't feel that it is the same people saying the same things all the time.
Hope this helps.