One of the early PC word processors, MultiMate was a pretty solid success.
They did something very smart in their design of the software: they made it look like the Wang word processing software that was popular on minicomputers of the time. If you knew how to use Wang word processing, you could learn MultiMate in a few minutes. A template that explained the function keys was all you needed.
This allowed businesses to switch to PCs without having to spend a lot of time retraining their users.
Another feature of MultiMate was that it loaded one page in memory at a time. This seems like an inconvenience (and it was -- if you accidentally pressed PgDown, you'd have to wait until the page displayed, then press PgUp and wait again), but it made sense. In a time when few computers had hard drives and memory was limited to 256K (that K, not Meg), it allowed long documents to be created and edited. You didn't have to worry if the 200-page document could fit into RAM -- it would.
Still, what made MultiMate popular also contributed to its demise. People who came to computers without experience with the Wang didn't care that they were similar; they wanted just to be able to use a word processor. In addition, MultiMate was slow to add features and printer support that other word processors had as standard.
When Windows came along, MultiMate's parent company, Ashton-Tate, decided not to bother with it. It seems to be gone completely (the only software I could found with that name is used to manage the mating of cows by ranchers).