Like many of the things which have changed history, the "Rebel" campaign in Egypt started with a very simple idea. At the beginning of May, a group of young revolutionary activists launched a drive to collect signatures on a statement withdrawing confidence from president Mohammed Morsi and calling for early elections. They announced that their goal was to have more than 15 million signatories by the anniversary of Morsi's inauguration on 30 June.
Few can have expected the idea to get very far - its initiators had no organisational machine to turn slogans into reality, and did not even share a common political platform.
Yet within days the campaign was spreading like wildfire. In just over a week the first two million signatures had rolled in. By the beginning of June they had reached the half-way mark: 7.5 million. A week before the 30 June deadline, campaign organisers announced they had hit the target of 15 million.
Nor was this another case of digital effervescence, measured in "likes" on a Facebook page or Twitter followers. Rebel activists collected signatures on paper, complete with the number from the National Identity card which every adult Egyptian carries. They became a common sight, from the poorest informal neighbourhoods to downtown Cairo: stopping cars in street at the traffic lights, mingling with the crowds at religious festivals and workers' protests. Those who were barred by illiteracy from signing their names provided fingerprints.
By now Rebel was more than a petition. The campaign organisers announced a week-long series of protests, with marches converging on the presidential palace. The Muslim Brotherhood and their Islamist allies called for counter-demonstrations in solidarity with their embattled president.
Rebel's stunning success needs to be set in context. It is an index of the crisis of the Islamist movement that a mere year after Mohammed Morsi took office as the first democratically-elected president in Egypt's history, more than 15 million voters are calling for early elections.
The speed with which the Muslim Brotherhood has squandered the credibility it built up during years of patient work under the old regime - including years of prison and torture for some of its leading activists - is astonishing.
The underlying reason why the Islamists' crisis is so acute is connected to an issue which the Rebel campaign doesn't mention, however. It is not merely the failure of the revolution's democratic promise which explains the cycle of repeated mass mobilisations, but its inability to deliver on the hope of social change. Or, more accurately, it is the combination of worsening economic and social crisis, raised expectations that the revolution will deliver social justice for Egypt's poor, and - most importantly - the fact that the poor, with the organised working class at their heart, remain mobilised on an unprecedented scale.
According to statistics collected by the International Development Centre, workers' protests and strikes made up 33 percent of the 864 protests recorded in January 2013, while just over half the total number of protests concerned social and economic demands. In March 2013, the total number of protests jumped to 1,345 (including 334 by workers), followed by 1,462 protests in April 2013 (including 462 by workers). This compares with a total of just under 4,000 strikes and social protests during 2012.
The timing of the latest upsurge in social protest is also important. At the moment when revolutionary activists whose sole compass is the movement in the streets were disorientated and demoralised, mobilisations in the workplaces and poor neighbourhoods surged ahead.
Rebel's success is also a sign of the weakness of their mainstream secular opponents. Liberal and Nasserist leaders, such as Mohamed el-Baradei and Hamdeen Sabahi, were riding high on the wave of protests over the constitution in December.
Yet they wasted the opportunity to build a mass movement against the Brotherhood connecting the social and political grievances of ordinary Egyptians, instead concentrating on cementing an alliance with figures from the old regime, such as Amr Moussa, a former minister under Mubarak. It took an initiative from below, by a group of young revolutionary activists outside the leadership of the mainstream parties, to rekindle the protests against Morsi.
The crux of the problem for both the Islamists and their opponents is this: the core institutions of Mubarak's state remain intact and they see no alternative but to make a deal with them. True, some of these institutions, such as the judiciary, are partially paralysed by internal warfare between the Brotherhood and old regime loyalists. The Brotherhood has also recently managed to claw open a few more spaces for its appointees, for example in the powerful role of provincial governors.
However, the fact remains - as a graffiti mural in Mohammed Mahmoud Street in central Cairo puts it bluntly - "the interior ministry is just as it was". Likewise the leadership of the armed forces, having retreated to lick its wounds after the disastrous experience of direct rule during the first year-and-half of the revolution, is simply the second rank behind Mubarak's old comrades-in-arms.
Rebel's explosive birth is therefore fraught with both promise and danger. It demonstrates beyond any doubt the continued vitality of the revolution from below, and the weakness of the reformist politicians - both of the Islamist and secular varieties - who hope to benefit from it.
Yet it also highlights the danger that unless the revolution gives birth to a movement capable of welding together the energies unleashed during the social and political struggles of the past two years into an instrument capable of breaking down the old state, it may be Mubarak's generals and policemen who have the last laugh.