One company hopes to use cryptocurrency to finance journalism. Another is using artificial intelligence to help people snare the best hotel prices. A third is making an extremely low-powered microphone for portable voice-activated devices.

All three are in our latest group of startups we think are worth watching. The nine firms are in a wide variety of businesses—from real estate to stock trading to cybersecurity. But all are disrupting existing businesses. Several are using AI technology, such as Hopper, StockSmart and Darktrace.