I've been spying on my neighbours.

I've been listening in on their conversations, stealing little snapshots of their lives. Don't be too alarmed - they've also been spying on me. We're all in this game of espionage together.

No, it's not Neighbourhood Watch - it's location-aware twittering. If you've been twittering within a 5km radius of me, I might just know about the film you enjoyed on Sunday, or your thoughts on the roadworks...

OK, such voyeurism is admittedly not that interesting. Yet.

I'm fairly new to the 'mobile web', having suffered for too long with handsets that take you to a 'web portal' with news from your friendly network provider and poorly displayed text-pages (that cost a fortune to view). Thankfully Apple have helped shake up the market, and more and more people are starting to experience the mobile web in one way or another (with shiny iPhones, or any number of other newer phones that are addressing the less-than-perfect user experience of yore).

As everyone knows, the uptake of mobile phones has been an incredible modern story. The penetration is so great, people will probably think you're pretty strange if you haven't got one. Behaviour has changed for everyone - even if you don't carry one you'll find that decision affects the people who want to contact you. It's hard, as they say, to imagine how we ever lived without them....

So now that serious uptake of the mobile web has begun, will it be on a par? Will it change behaviour as dramatically?

I think the answers are "yes" and "yes" again, which is why I went on Tuesday evening to a Chinwag event about mobile search and location-based services. It was a panel discussion, chaired by some interesting people from nascent (and more established) businesses seeking to really capture a part of this new territory. These including Taptu (mobile social search), Rummble (for personalised recommendations), Plazes (a mobile social network) and The Cloud (the Europe-wide WiFi hotspot service).

A great deal was discussed through the evening, but I'll focus on a single area.... spying!

Well, almost; let's call it the 'tracking versus publishing' problem.

The technology behind location-finding, whether GPS or cell-tower triangulation, has existed for some time. Now that a great number of people have access to it on their phones, the types of location-services and applications we'll see will take on new levels - as early uptake fuels investment fuels interest and so on.

The advent of such things as location-aware social networks that allow you and your friends to see where you all are, or services that provide information about the area around you, raise large questions about privacy and security. You may be happy to tell your close friends you're in the Queen's Head, but do you want your colleagues, or ex-partner, to know?

Just as mobiles have made us ever-reachable, and completely changed the way we organise our social lives ("I'll just call you when I get nearby and see where you are"), location-based services are ripe to push us further into a strange new 'ever-locatable' world... or are they?

How much of our privacy are we willing to give up? How much will we be forced to?Data about our location has been available to network operators for a long time, but this never greatly concerned people. The use of sat nav systems like Tom Toms have educated people in location-tracking, making them more comfortable with such technology. But neither of these things involved the sharing of data, and its in the means of sharing that the complexity, and problem, lies.

Tracking is passive, and the lack of control is understandably unsettling. Publishing is active, and the ability to choose what and when you share is likely to prove more comfortable for the majority. But will a location-aware social network offer value if people only publish their location every other day? The reality, perhaps, is that a midway point between tracking and publishing may be the only way to create valuable services. Granular privacy controls could allow detailed control of automated publishing, with one group of people able to see where you are from 9 - 5, and another from 5 - 11. Or, perhaps, a zone that allows tracking once you enter it, but ceases the moment you leave. Or how about varying levels of accuracy - I'm either in London or I'm right next to the Tate Modern entrance....

Research into privacy controls, however, has revealed an interesting common attitude. Most people feel strongly that they want granular control of their privacy when using online services, but only around 5% ever actually adjust these settings from the default. If this proves true for location-aware services, what does it mean for privacy in practice?

No one yet knows, but the answer lies in the hands of the people dreaming up new services and applications, some of which seem bound to capture our imagination and forever change behaviour. It's a considerable responsibility, in a fascinating space.

I'll be spying on it.

See you at N 51°30'29'', W 0°7'41'' in an hour.