In the six pages of coverage given to new social networking phenomena Foursquare and Gowalla in the latest issue of Wired magazine, the words ‘privacy’, ‘safety’ or ‘security’ do not make a single appearance. Yet these are just two new social networking sites that don’t just want to know what you are doing as Twitter and Facebook do – they want to mark your exact location on a map, with pinpoint accuracy. Scary? No, it’s terrifying.

For someone who has complained at the potential invasion of privacy already foisted on an often unwitting public by social networking sites – which fall back on the argument that people have opted into their services and so aren’t concerned about privacy – the thought of people telling the world their exact location at any point in time is incredibly concerning.

The privacy storm that engulfed Facebook recently, prompting it to update its privacy settings and procedures, has so far swept right past these new darlings of the tech industry: Foursquare, Gowalla, Brightkite and Loopt to name a few. After all, they could turn out to be the next Twitter or Facebook, and make their founders and investors instant millionaires.

How social networking got location-savvy

With Foursquare and Gowalla, you create a free account on their website in a few clicks, and perhaps download a small application to your laptop, smart phone or dare I say, iPad. You can then ‘check in’ to the site when you are out and about, or just idling at home. ‘I’m in Starbucks,’ you might say. ‘I’m in Starbucks again,’ you might say the next day. But here’s the really good bit: the systems use the GPS chip in your phone to map your exact location, and then show that map to anyone in your social network.

If you check in to a particular location like a Starbucks more than anyone else you get a badge – an electronic one, of course – to say you’re a regular, or even the ‘mayor’ of that Starbucks. If you show that badge to the staff at a Starbucks in the US, they’ll even give you $1 off any Frappuccino. Whoop.

Before we ask why anyone would want to keep telling the world where they are, let alone show them on a detailed map for a paltry discount on a coffee, let’s just look at some of the obvious implications.

‘I’m cold and I’ve lost my mum,’ a young girl says, mapped precisely to a remote avenue in a vast park, near dusk. ‘I’m at home on my own all weekend – the old man’s on a trip!" a young lad says, with an accompanying map. ‘Just parked my brand new Ferrari on 6th Street, hope it’s still there when I come out of my meeting LOL’.

So what are the checks and balances, the safety measures that these sites have taken to ensure that their users don’t do anything that puts themselves at risk? Well you may ask. Foursquare and Gowalla – the two leading the geolocation social networking charge – won’t let anyone under 13 years of age join their sites. They’re adamant about that, and incredibly strict. Not.

On Foursquare, for instance, you have to enter your date of birth when you sign up, to show you are over 13. They don’t check that against a database to ensure you aren’t lying about your age, of course, but still, it’s something, right? Gowalla won’t let you join if you are under 13 either, but it doesn’t even ask for your age when you sign up.

Of course, not just anyone can see your location when you ‘check in’ to these sites remotely, only those in your network. Safe as houses, right? Nope. Kids may well be flattered that a good-looking young 15 year-old wants to be in their Gowalla network – only that good-looking 15-year old is in fact a 30 or 40-something year-old called Derek.

Even without faked identities, there’s the fact that many won’t have the time or energy to rigorously approve everyone in their network. They certainly won’t read any fine print about using such sites safely.

Taking privacy seriously

I asked Foursquare – which has 1.5 million users and counting – about my safety concerns. Am I missing something? Apparently not. "We take our users’ privacy very seriously," their spokesperson assured me, "and we’ve taken several steps to ensure that users are able to control how and when they share information with other people. First of all, a user’s location is never automatically shared – they need to choose to check in when they’re at a particular venue, and the only people that can see their check-ins are those people that they’ve accepted as foursquare friends."

"When they check in, they can decide whether or not they want to tell their friends they’ve checked in, and whether or not they’d like to publish this information to their Facebook and Twitter accounts," they added. "They can also choose to check in ‘off the grid’, which means that their friends will be able to see that they’ve checked in and they can receive badges and points for the check-in, but their location won’t be shared."

In other words, when you ‘check in’, you need to make sure you check in ‘off the grid’, i.e. ‘opt out’ of the mapping aspect of such sites. I’ve written before about the difficulty in expecting anyone to opt out of anything. Suffice to say it’s not foolproof, even if someone understands the risks.

So what’s the benefit of these new geolocation-based social networks – why are they the talk of Silicon Valley, on the front cover of Wired magazine, and counting user growth in the tens of thousands a day? As in the Starbucks example, users are encouraged to earn badges by ‘checking in’ at a location more than anyone else. You could collect badges for checking in more times than anyone else, logging in late at night (I kid you not), being the first to register a place, or even doing a long journey that you log into the system.

It’s hoped more companies like Starbucks will reward users who come back often – though there’s nothing to stop you ‘checking in’ thousands of times without ever actually buying a coffee.

Life becomes a game, played out on a Google map.

Your friends – your real friends at least – might like to know you’re in town and fancy a beer. They might appreciate you telling them you had great service at a particular restaurant in their neighbourhood. They might not have known about a little antiques shop down that alley behind the cinema. All of which is good, and interesting, and potentially valuable. And all of which you could tell your friends without showing your location on a map – indeed without joining a social networking site at all. As they say on Twitter, #privacy, man.

Photograph: Getty Images.