Recently, Glass has also triggered animosity of another kind in Google’s own backyard. In February social media consultant Sarah Slocum was accosted in a San Francisco bar while wearing the device. “You’re killing the city!” said one woman as she tried to snatch Glass from Slocum’s head. Some now view the device as an objectionable symbol of a wealthy Silicon Valley elite – an elite they say is pricing poorer residents out of the city.

It didn’t take long for critics to emerge. Writer Ed Champion catalogued ‘ 35 arguments against Google Glass ’, from anxiety over ever greater personal data collection by Google to the potential for distraction during conversations. Meanwhile, the privacy advocacy group Stop the Cyborgs , based in London, warned that the device’s video camera could be used for intrusive surveillance. “Authorities, corporations and lawyers will be able to access everyone’s footage under the relevant electronic communication act,” the group wrote on its blog.

The hype and the controversy surrounding Google Glass began in April 2012, when the company released a much talked about concept video , revealing the capabilities of Glass – responding to voice commands and recording video through the eyes of the wearer, for instance. Then last year, a beta version was made available to a limited number of “explorers” at a cost of $1,500 plus taxes.

Yet for many, one of the most significant concerns is that Glass allows users to record photos and videos of others without their consent. Unease about covert image capture has caused Glass to be barred from a string of bars, restaurants and other locations. This hostility has even led to the coining of a new pejorative, “glasshole”, to describe users who don’t respect the personal space of others.

In other words, perhaps the greatest obstacle Google faces if it wants us all to adopt Glass is its potential to disrupt existing social norms and aggravate our interactions with one another. Unlike the personal devices in our pockets, it sits right there on one’s face, perpetually demanding a reaction from others.

Laura Freberg, a psychologist at California Polytechnic State University and Google Glass owner, believes society will develop a new etiquette for using head-mounted technology in social situations, but it will take time. People will need to work out where and when the use of such devices is acceptable to others.

“I walked into the restroom and was like, ‘oh my gosh... I’m going to make people really uncomfortable’,” she says. “It’s a learning process for the person who is wearing it as much as it is for the people around you. I think developing good manners will help us work through a lot of these problems.”

A small study carried out by Freberg’s students, for example, found that someone who started using Glass during conversation was seen as more distracted or rude than someone who began using a mobile phone. She adds that, to be successful, the device should be as physically unobtrusive as possible because humans, who learn to read faces for emotional information at a very early age, may be instinctively distrustful of anyone whose eyes or eyebrows are unusually obscured. More subtle editions of Glass which use traditional glasses as a frame have indeed been recently announced by Google.

Bill Buxton, a principal researcher at Microsoft Research, also believes it will take time for society to evolve the social norms around wearable computing technologies, in a similar process to the establishment of mobile phone etiquette. He also notes that with more and more gadgets like smart watches and intelligent wrist bands under development, tech companies are under growing pressure to engage in debates regarding privacy and other social issues related to such technology.

“We dismiss too quickly concerns about privacy, intrusion and other repercussions amongst our peers, in our enthusiasm for adopting the latest and greatest, newest technology,” he says.