Robin Sloan explains the larger context of Google Glass better than anyone I’ve heard.
(Sidebar: while walking home from work in mid-May, I passed by a Asian man in his mid-40’s wearing a pair of Google Glasses. He looked world-weary and exhausted. I like to think that he was coming home from a 16-hour workday at the Kendall Square Google HQ and was exasperated after his supervisors asked him to take a beta unit home. The end of the glass cube over his left eye appeared to contain a tiny red LED which blinked against his face, the only indication of a HUD the rest of us could not see.)