Remember [Lotus Notes] it was originally designed to handle the CIA's email back in the 1980s. It had strong encryption, distributed directory management, digital signatures, distributed certificate management, and a host of other capabilities that were decades ahead of its time.

Every time you received a Notes email (or indeed any kind of document) from another Notes user, it was automatically authenticated; no imposture was possible, and this was at a time when it was normal for SMTP to accept any input from any source that knew the IP address. At the time I was training people on this new email thing, and I'd open up a telnet session to the server and show them how I could forge an email from "The Lord God Almighty" with the subject line "Don't believe anything you read here."

Notes was never a bad email system. It had a very awkward client UI and a server that required a more than room temperature IQ to administer, but you got things in return that people in the 90s didn't understand to be important yet. Things like two factor authentication and local encryption. If you lost your laptop, the data in Notes would result in a data breach. People still haven't figured out how to prevent that in a way that is affordable and simple to use and administrate. So while it was inexcusable that they never hired some HCI experts to clean up the archaic user interface, you still got a very modern set of capabilities all the way back in 1990s. People were frustrated with the complexity, but to be fair while Notes was asking you to handle things like generating and signing crypto certificates, you didn't even have the option with anything else back when it was introduced.