I always got the impression that Lotus Notes was a great idea, but very poorly implemented. The concepts in it were good, it was just a shame it inflicted so much suffering.
Sure, I can build CRUDish apps with Django, but there are simple use-cases that take me a week with Django, that would have been a day with Notes. It's crazy that things are slower for me 20 years later. I'm pretty sure I'm not dumber now.
http://www.filemaker.com/products/filemaker-pro/
"FileMaker Pro is no longer available. It has been replaced by FileMaker Pro Advanced which includes more features to help you develop and deploy custom apps faster and more efficiently."
1 - Document Store (iirc, CouchDB was inspired by Notes/Domino)
2 - Replication - even past the 90s, it was one of the best tools for disconnected users
3 - Low barrier to application creation (it was about as easy as building something in Filemaker Pro)
4 - Easy publication of applications to the web (this was BEFORE 2000, so kind of a big deal back then)
5 - Administration of servers was pretty easy
6 - LotusScript (similar to vba) let you go much further than the prebuilt formula language (if you were willing to learn it)
Keep in mind, these benefits were available pre-2000, and in that time many were strong competitive advantages.
Hell, I don't even think all laptops had ethernet ports back then either. In a lot of cases, you had to buy PCMCIA cards for that.