Back in the day, I really enjoyed reading Nat Friedman's blog (yes, he of Novell/Ximian/MS/GitHub fame) about a broader system called Dashboard which provided a sort of live querying of your data based on activities you were performing at the time. It's mentioned on Slashdot at https://developers.slashdot.org/story/03/07/27/1849258/nat-d... but sadly his blog does not appear to be archived anywhere.. if anyone has any more info on it, do share as I was fascinated by it at the time. Maybe once he has wrapped up at GitHub I could gently prod him about it.. :-)

(Found a blog post from 2003 where someone actually described it as "a system wide Rememberance Agent"! https://www.oblomovka.com/wp/2003/07/12/nats-dashboard/)