I feel like note taking/personal knowledge bases are still an unsolved problem (with many attempts) and there will be a disruptive technology in this sphere at

I feel like note taking/personal knowledge bases are still an unsolved problem (with many attempts) and there will be a disruptive technology in this sphere at some point. People often take a shot at this problem, which makes for the monthly or bimonthly thread on HN, but I think there's still a lot of room for innovation.