Technology played a decisive role in helping Muhammadu Buhari become the first Nigerian to oust a sitting president at the ballot box, from social media campaigning to biometric machines preventing the widespread rigging that marred past polls.

Three decades after seizing power in a military coup, part of the 72-year-old former general's appeal to the electorate in Africa's biggest economy lay in his successful rebranding as a man who embraced democracy.

A good deal of that rebranding happened online, where campaigning from smartphones can build momentum at low cost.