Remember how douchey the bluetooth headset people were? Very small by comparison, and that was mostly hidden if you had long hair, or were viewed directly from the front.
The Pebble is about the limit, which is why the wrist-computer thing is so interesting, even though it doesn't provide a huge amount of new capability for "heads up" computing vs. a vibrating smartphone. I'm mostly unwilling to wear the "old" Pebble, but probably will wear Pebble Metal, and will definitely wear Pebble 3.0 (if it improves by roughly the same amount; 1-4mm slimmer would be nice).
Glass would be fine alone, or in a car, or in the field, but probably not something I'd wear at dinner, or in a casual meeting (unless by using it I were much more productive and useful).
The article seems to think wearing headphones in public is ok. It's fine when you're sitting down avoiding people, but the kids wearing large, crappy headphones in other environments (e.g. at meals) are kind of pathetic.