I worked for a large financial (~80,000 employees) that decided to move to Notes from in-house exchange servers well after it was obvious Microsoft had won the productivity wars. Rumor mill suggested it was brought in at the direction of a board member who just so happened to have close interests with IBM.
It set overall productivity back by at least 5 years before executives were forced to make a very decisive and quick move to O365. The reason given were scalability issues, the overwhelming cost of purchasing P-Series hardware (6-digits for one server) by the rack to keep up with demand along with the cost of developers attempting to make something useful for all of the different business needs.
Last I checked they are still stuck with some small, but essential work being diverted through Notes despite the move back to Microsoft.
One such contract was to exfiltrate a Notes based application and it's data in to a new application. Apparently integration was the real issue at hand and I can understand why after just dipping my toes into Notes. I can see how easy Notes is to create things, It was nicer than MS Access IMO. But trying to reverse engineer from said apps was painful to say the least. It turns out that the app in question ws so broadly hated, that 3 different groups had already been doing the exact same thing, with 2 others looking into it. They decided to look at the different teams in place and pick one to move forward. It wasn't the team I was on that was kept and so ends my experience with Lotus/IBM Notes.
As a pure employee a few years earlier, Notes was pretty nifty, it was used to integrate just about everything in the company. Definitely gives insight into where a lot of Dilbert jokes came from, definitely from Notes. Though allowing JavaScript in HTML email with early Outlook was a really bad design decision as well.
When that company moved off of Notes despite the massive investment, the writing was on the wall even if the product survived for a few decades under IBM.
>Lotus Notes is used by millions of people, but almost all of them seem to hate it. How can a program be so bad, yet thrive?
I think half the issues people have with AI today are simply because AI has seen just as much slop in the real world as it has "good, clear code."
The boots on the ground cried "ugh, Lotus Notes!" in unison and just had to deal with byzantine key combos, nonstop client crashes/unresponsiveness, and moronic UI decisions some 3-person team made in like 1987.
I have opinions.
I don't recall the client having much crashing and unresponsive issues, but I do recall people finding the UI unintuitive compared to MS products, and of course the custom products built with Notes could vary quite a bit. But so does the web, particularly the early web.
But then you can say the same thing about people building Excel apps and that has been a selling point. Or Powerpoint presentations that people complain about but keep using.