With so much hype surrounding new technology in mobile marketing, it's time we remembered one of the oldest social networks at our disposal: our address book.

There are a lot of things that spring to mind when you think of 'wasted opportunities', but would the mobile phone be one of them? Surely not, considering the increased hype about 2008 being the year that mobile marketing finally takes off and the new innovations being announced almost daily.

But when you look at the actual applications that are featured on almost every handset, most are disappointingly dull. Take the mobile phonebook for example. It is one of the most used features of any gadget, ever, perhaps with the possible exception of the iPod click wheel. Yet this feature -- that every single mobile owner uses every time they pick up their phone -- has been all but neglected.

It's an interesting paradox: here is the most frequently used application on the mobile, in which we store our most valuable data -- our connection to our closest friends, family and business associates and the real life social network that we have been building up over years -- and it's left untouched? 

In fact, there hasn't been any development to this static feature for the past 10 years -- unless you count adding a 'speed dial' function as something to get excited about. But that's hardly Web 2.0 is it?

With the proliferation of online social networking, the natural next step for the mobile phone contact list is the integration of your online life and your mobile life. The idea is that the information stored in your contact list isn't simply a name and number, but useful information your friends want to share -- this could be where they are, what they are doing, their latest post on their Facebook profile, or the holiday photos they've just uploaded to Flickr.

Key to this integration, though, is the ability for people to control their privacy settings, so the user makes the decision about what information they want to share and with whom.

Once this integration has been achieved, it will create a range of interesting marketing opportunities. As long as the consumer has agreed to make their information available, particularly location-based details, responsible marketers will have the ability to undertake outreach that is relevant to an individual's social interaction and information needs.

Marketers can and should be part of the 'Mobile 2.0' revolution, providing people with a useful and relevant mobile experience. That's the missed opportunity.

Connecting a person's online life to their mobile life is where the real opportunity lies. Allowing consumers to enjoy the benefits of both worlds while on the move, anywhere, at anytime, is what makes this opportunity so powerful.

Ed Bussey is COO, Zyb.