We already carry smartphones – do we actually need wearable computers or are they just a fashion faux pas?

The first surprising thing about Google Glasses is that anybody thinks this is a new idea (just have a look at this history of mobile augmented reality). Steve Mann, a Canadian known as the father of wearable computing, has been developing systems since the 1980s with obvious industrial, medical and military applications. One example is the Battlefield Augmented Reality System, where having information overlayed on your view of the world could be a matter of life and death.

The second surprising thing is that we aren't all wearing computerised glasses already. In a 2001 Guardian article titled "From man to borg – is this the future?", I quoted a wearable computers website claim that "large scale acceptance of wearables in the general consumer market will surge in about 2005. By 2015, wearables will have virtually eliminated desktop, laptop, and handheld solutions altogether". That turned out to be over-optimistic.

Early users of wearable computers with head-mounted displays considered it a triumph if people didn't cross the street to avoid them. If they needed to carry a GPS unit, an accelerometer and a video camera as well as a computer, it was a rucksack of extra baggage.

Today, however, most of us carry a mobile internet computer terminal that packs all of these capabilities into one light, pocketable device. It's called a smartphone.

The one thing we don't have is the head-mounted display, which is the problem Google Glasses (which take signals from a Google Android smartphone) can solve.

But Google is just one of hundreds of companies working on similar ideas. Interestingly, Apple was applying for patents on head-mounted displays in 2008, and later it hired wearable computing veteran Rich DeVaul. So your iGlasses may be coming.

The tricky questions are whether anyone actually wants a head-mounted display. If you were a soldier, for example, you would want to know if there were snipers hiding behind a wall, and if you could bring in a drone (pilotless aircraft) to fire at them. As a pedestrian crossing the street, the sudden appearance of a special offer from a nearby carpet retailer might have less happy consequences (since this is Google, you can bet ads are part of the master plan).

There's a much simpler way to do augmented reality: just hold up your phone and turn on the camera. Plenty of apps already do that, and here are 40 of the best.

Google's glasses rely on information fetched from the internet but there's no reason why extra data cannot be provided by government buildings, pubs, bus stops, advertisement hoardings and other street features that can talk to most smartphones by a variety of means – Wi-Fi, Bluetooth, RFID (radio frequency identification) chips, NFC (near field communications) etc – to create smart places.

In the future, "augmented reality" is going to meet an augmented reality, as the virtual and physical worlds combine. This is, inescapably, the way technology is going. Whether Google Glasses will be part of that future remains to be seen.