The most famous and loved will always be the balad of the Active lands of Plasma where the society became so enlightened they managed to expel the Royal Society for Putting Things on top of other things.
What the future (KF5) brings?
Ok, stopping with the story now.
KActvities are back in the world of semantic linking, this time without Nepomuk, and without any unnecessary performance overhead. The new service implements all the features Nepomuk provided for activities, but also goes a bit further than that.