Simple explanation of some things
Akademy is the yearly conference for KDE Contributors and other interested persons.
Baloo is the new file indexer
KDE eV is the non-profit organization supporting KDE and keeps KDE's assets.
Nepomuk is the old indexing service, now mostly retired.
Okular PDF reader released as part of KDE Applications
Randa is a remote place in Switzerland where Mario Fux close to every year arranges a large week long hacking sprint.