"AI winter" is a pretty official term -- it even has a Wikipedia entry. I actually don't think neural networks are just hype, any more than previous AI technology was just hype. A lot of great things have come out of AI research -- logic programming, expert systems, even genetic algorithms -- but each in turn failed to deliver on the unrealistic expectations that were built up around it. We see pictures of ANNs hallucinating, and they seem to promise machines that can dream. But in reality an ANN is just a statistical model trained on a large corpus of inputs belonging to a particular domain. They're profoundly effective at what they're good at, and it's cool to see them pick apart a picture and tell you what's in it.

However, I've been hearing crazy talk, especially in the popular press, about how strong AI is just around the corner, how AIs will soon replace people, what will we all do when machines can do everything for us, and so on. It's been repeated on a ten to fifteen year interval since the dawn of the computer age, it's no more true than it was the last time, and we should know better by now!