I decided to hide old-system avatars so that people would wonder where their avatar went and visit their avatar settings.

At which point they'd see a special message I show people with old-system avatars and upload their avatar into the new system (which removes their avatar from the old-system, hiding the special message forever). :sun

I'll bring back the spirit of the frontpage news box as an actual notification that lets me announce new features (that matter) and link to some post where I ramble on in more detail (if applicable).