Went to CES, couldn’t decide, so bought the lot. Credit: Robert Scoble

This week's Consumer Electronics Show in Las Vegas has offered up a veritable smörgåsbord of wearable technology. We've seen devices of all kinds to tempt us into this new age. So now is the time to decide what you want from them and how much information you are willing to hand over to your friend via your arm.

Depending on how you define the term, "" has been developing since the mid-1990s or since the advent of spectacles or even clothing. When were first introduced to the market in the early 2000s, these tended to be quite bulky devices in the form of boxes in bags or on belts that were connected by trailing wires to the headset and control devices.

What is different about the new wave of wearable technology on display at CES is that it puts the digital on to the person. And what unites most of the devices we've seen is a central purpose: logging.

What's changed?

Now, the miniaturisation of processors means that it is possible to put hefty computing capability into something small enough to be mounted on the wrist or on the head. That said, most of the products on show at CES need to connect to other, more powerful processors, either a phone or computer, even if it can be done wirelessly.

The choice of where to place the wearable technology on the person is split between the head, following the design pattern of spectacle frames, or the wrist, following the design pattern of the watch.

We’ve come a long, long way. Credit: Glogger

Even while they stick to the traditional in terms of where they aim for on the body, device makers are battling out to produce something different now that their wares are being seen as the next big thing.

The Martian Notifier, for example, is selling itself as the incognito smartwatch. It subtly vibrates in different patterns when a different type of message – such as an email or social media mention – comes your way.

The Pebble Steel is at the vanguard of 's attempts to do fashion. Where rivals continue to be made in plastic materials, it can be bought in brushed steel, so it will go with your suit.

For those who want to go for the face, we've seen GoogleGlass, Lumus DK40, Ora-S AR Eyewear, Pivothead Smart Colfax.

For those who want to keep it to the wrist but don't want a Pebble Steel or a Martian, there is the LG Lifeband, Wellograph Sapphire Wellness, Sony Core, and the ZTE Bluewatch.

The Pivothead Smart Colfax

Not only do the wearable technologies on show at CES fit their processors into small spaces, but many include some form of sensor, either a camera, or sensors that collect data relating to movement or physiological conditions.

The LG Lifeband, for example, can record your movements and tell you how many calories you've burned. The Sony Core tracks you too, but also lets you log noteable moments.

These choices of sensors reflect the current trend to develop wearable technology as a support for logging. Those on the head are most often used for life logging. We'll be able to share our daily lives with friends or even strangers by recording what we see.

Those on the wrist are predominantly aimed at health logging, supported by physiological sensors. Then there are those worn on the head that are used for augmented reality, with digital content projected directly in the viewer's line of sight and overlaying their view of the world.

Because they all log, these devices necessarily raise questions about privacy. Any attempt to expand their use beyond early adopting enthusiasts will need to address these concerns. While fitness fans might be happy to share their every triumph with others online, others will want to feel more in control of some the most personal data they have.