Ibrahim's Celtel is operational in 14 countries across Africa and has been instrumental in the second revolution, which is connecting people in different ways. The company introduced the "One Network", which scrapped international calling rates for Celtel to Celtel calls. So you can be in the heart of Kenya's Rift Valley and call someone in the middle of Virunga National Park in the Congo for the same price as calling a friend in downtown Nairobi. This was the first time anywhere in the world such a scheme had been introduced. It hasn't happened yet between the US and Canada or between France and Germany.

Now the scheme has gone one stage further. Celtel was sold for 3.4bn dollars in 2005 to a Kuwaiti firm called MTC. Last weekend MTC rolled out its new network name, Zain, and linked up the One Network across all the countries in its group, from Africa to the Middle East. That guy in Congo can now call a friend in Iraq and be charged a local rate.

The immediate change in Kenya though has nothing to do with calls to Iraq. Like many countires on the continent, shops, shacks and stalls across Kenya are painted in the colours of the leading mobile phone networks - it's a cheap form of advertising which benefits the shop owner too  - he gets a nicely painted awning.

The bright green of Safaricom and the red and banana yellow of Celtel decorates shops throughout the country. The red and yellow has gone now. When Celtel became Zain last weekend all the old adverts and shop fronts were replaced with the corporate colours of the new network. It was only this weekend, when I took a bus trip south to Tanzania, that I realised just how dramatic the Zain takeover is. Every single shop that used to be Celtel red is now painted in the colours of Zain.

Unfortunately for the shopkeepers, that colour is pink. And not just any old pink. This is a bright, ultra-pink, the sort you notice from a mile or so down the road. Still, at least no one will miss their store.