Newsnight correspondent Paul Mason travels through Kenya using a map of the country's mobile phone networks as his guide. Part two of this story appears tomorrow.
"How big a change have cellphones made to Africa?" I shout the question at Isis Nyong'o, over the throbbing bassline of a Kenyan ragga track. She tells me calmly: "It's had about the same effect as a democratic change of leadership."
I'd expected hype from a Kenyan-American executive at MTV Networks Africa but by now I believed the hype myself. It was not the bling, the fashion models with candy-floss hair - it was the Nairobi teenagers mobbing the entrance to the city's Carnivore club and overwhelming the Motorola stall.
If this was just an event for the elite then neither MTV nor Motorola would be there. Kenyans have been voting via SMS for their favourite rap stars, and the whole event has been promoted via mobiles.
With one in three adults carrying a cellphone in Kenya, mobile telephony is having an economic and social impact which is hard to grasp if you are used to living in a country with good roads, democracy and the internet.
In five years the number of mobiles in Kenya has grown from one million to 6.5 million - while the number of landlines remains at about 300,000, mostly in government offices.
I decided to make a journey through Kenya to gauge the impact on the ground: the plan was to go from Mombasa via Nairobi to Lake Victoria following the mobile network map - contrasting life on the network to life off it.
"Hard luck," said my driver, Daniel Wambugu. About 80% of Kenyans are covered by mobile networks and while it would be easy to find a place off the network, finding people there would be difficult.
Kenya's rap award winners were chosen by text message
He suggested dropping Lake Victoria for somewhere in the Rift Valley to see if we could find a remote Masai village. Right, I said.
But first there was Mombasa to take in. It's a city with a sleepy, post-colonial feel where the most dynamic people are the Matatu drivers who zip between the traffic, shouting and bawling and getting themselves arrested, breaking down and (they allege) bribing the cops to let them earn their daily bread.
These manic minibuses drive their owners mad. "Sometimes you don't sleep," said Abdul Khan, who owns three. The two big problems are repairs and bribing the police, he tells me.
As it turns out the whole Matatu industry has been revolutionised by the mobile phone. It's not rocket science, it's just that if you need a new brake block, you don't have to walk to the shop, find the owner, do lots of face to face business, walk back, have lunch etc. Likewise with getting your driver out of the police station. Business happens faster.
Soon you will even be able to pay for a trip by Matutu by mobile phone. To find out how I zipped across Mombasa to the offices of Safaricom, one of the two network providers in Kenya, part owned by Vodafone. It let me film the launch of a project called M-Pesa - and, read my lips, I said "launch" not "trial".
M-Pesa does not look spectacular.
It is simply an extra line on your mobile phone menu that says: "Send Money". You go to an office, transfer funds onto your phone account, and then send them to your friends, or family, or anybody else with a mobile. Then, they go to an office, show the code on the mobile and some ID, and collect the cash.
Even just working in Kenya it's going to revolutionise things - because plastic money and bank accounts are not greatly in evidence in this country as more than 50% of its people are classed as living in abject poverty.
M-Pesa could make mobile payments a reality
But once it goes global - and Vodafone says it will - then the $93bn of remittance money sent by migrants to developing countries each year could start flowing this way. Basically mobiles could be about to make Africa a very much more liquid economy.
After this I set off on my journey from Mombasa to Nairobi up the single highway that links East Africa's main port with the interior: it was a case study in what's been wrong in countries like Kenya.
Despite millions of dollars in aid money, the Kenyan government never quite got round to finishing the road. This key piece of infrastructure is now being upgraded by Chinese engineers in return for an oil deal. It is testimony to the kleptocratic elite's inability to do the simplest things.
Even the railway that runs alongside the road is, say locals, similarly shambolic. Contrast that to the mobile network which it is excellent all the way along this main artery.
It was built in four years, by Celtel and Safaricom. Admitted, building a network of generators and masts is easier than laying mile after mile of tarmac in an area known for man eating predators - but to many Kenyans the contrast is telling.