Good riddance. It was a bad idea at the time and still is, just like the Semantic Web itself. Nepomuk was complex and fragile, as was Akonadi; I've lost count of the number of times I was unable to read my email because this supposedly "optional" piece failed (usually due to an akonadi problem). In the end I resorted to https://www.trinitydesktop.org/ - KDE3 which was less flashy, but worked.

This post is a good sign - maybe KDE is belatedly paying attention to user-facing functionality rather than academic technology exercises. Maybe I can switch back to "mainline" KDE.