Rediscovering Lotus Agenda (MS-DOS, 1989)
lock.cmpxchg8b.com
lock.cmpxchg8b.com
A couple of web pages and an user support forum are no substitution for a comprehensive, structured manual, nor is decent discoverability.
(Salesforce killed em all for a reason.)
As Bob Newell (linked in the article) notes, Emacs and Org seem to carry this torch today. There may still be a few tricks unique to Lotus Agenda and such tools, but Org mostly surpasses them, and its flexibility and extensibility go far beyond what Lotus Agenda and its primitive macro language could do.
Best thing is this doesn't break the flow of thoughts by forcing user to fill in dates, people etc. in different UI boxes.
I wonder how did they approach the NLP part in 1990 and what more is possible today with deep learning?