I understand the desire to advertise the new feature, but - from a communications perspective - understand that running the new Single Onion code requires adoption of a core Tor daemon codebase which isn't even in "stable" yet.
Facebook _are_ running Single Onions*, they're just nor running the 2.9 codebase yet, they're doing it the old way.
If you want to talk about "sexy sites" it's probably wisest to talk about those who use the feature, including Facebook, and then frame the 2.9 code as reifying/"making concrete" a feature which will aid performance for sites which want onion addresses but do not need to be reticent or anonymous.
-a