Once upon a time MetaFilter used to be a place to have interesting discussions, but I haven't been there for a decade or so it feels like and can't vouch for the current state.
Hey, me too. Was a frequent poster around the turn of the century, left around 2007, but was considering going back. It seems like Jessamyn West now runs it, which is nice. In its day, it was the smartest and most interesting discussion forum I've been a member of: I still measure everything else against it.