My favourite forum is
Reading Recommendations. I don't often contribute to it, but I've been lurking there since I joined MobileRead a couple of years ago, and it has helped me discover several authors that I probably wouldn't have come across otherwise.
I also often visit the French and German forums, but that's more to help me keep up to date with my language skills rather than to learn anything new about ebooks or readers.
With best wishes for the next ten years.
Mike