Cyc got hyped for while in the early 90s. It became apparent, however, that rule-based wasn't going to play as big a role as ML in the future of AI research. It still exists, but the company is really secretive, and hasn't released anything viable in years.
[edit: I wasn't alive back then, so most of what I know comes from the Wikipedia article and a recent HN thread: https://news.ycombinator.com/item?id=21781597 . My view of Cyc probably comes across as slightly negative. Their (Cycorp) view seems to have evolved since then, and they seem to be creating some really interesting stuff.]
