The Kony 2012 Cover the Night campaign woke up to awkward questions on Saturday after activists failed to blanket cities with posters of the wanted Ugandan warlord, Joseph Kony.

The movement's phenomenal success in mobilising young people online, following last month's launch of a 29-minute documentary which went viral, flopped in trying to turn that into real world actions.

The campaign aimed to plaster "every city, on every block" around the world with posters, stickers and murals of Kony to pressure governments into hunting down the guerrilla leader, who has waged a brutal, decades-long insurgency in central Africa.

But paltry turnouts on Friday at locations across north America, Europe and Australia left cities largely unplastered and the movement's credibility damaged. "What happened to all the fuss about Kony?" said one typical tweet. "Kony is so last month," said another.

Elissa O'Dell, 24, an activist in Los Angeles, put a brave face on the fact just her and two other volunteers attended the painting of a mural on an auto dealership off Santa Monica Boulevard.

"It's just been us the entire day," she said on Friday. Another campaigner took photographs while an artist painted the mural, which said "Our liberty is bound together".

"The point of Cover the Night is for our community of supporters to give something back, pick up trash, paint schools, some direct, local action," said O'Dell. So, where was everybody? "We didn't expect people here," said O'Dell. Supporters were to place posters in coffeeshops, fire and police stations and other locations. "The response has been terrific. Tomorrow people will wake up and see our posters everywhere."

But on Saturday the boulevard, and according to reports the rest of LA and other cities, were largely free of Kony.

The campaign also tanked on twitter. "Find the silence around #Kony'12 interesting. It's muted embarrassment from prior supporters, mixed with quiet smugness from detractors," said one tweet.