Google might not realize it, but Project Glass isn't alone in the patent race these days. Sony has quietly applied for a patent on a familiar-looking smart glasses system whose advantage over Mountain View would be an emphasis on things in twos. Eyepieces are the most obvious, but Sony is also keen on sharing data between two friends: transmitters on a pair of glasses would send personal info through a likely very uncomfortable glance at someone else with the same eyewear.
If your friends are more than a little weirded out from sharing by staring, the proposed glasses could still pick up information from visual tags on posters, products and virtually anything else. There's even the obligatory connection to a watch for sharing data with the rest of the world. More here.