By Martin Morgan
BBC Monitoring, Kiev
The yellow bandanas and five-minutes-to-midnight symbol of the Pora (High Time) youth movement stand out amid the orange banners of the Ukrainian opposition rallies.
Pora is the latest manifestation of Ukrainian political discontent, with its most immediate origins in the nationalist and democratic protest groups of the late 1990s.
Pora's street protests showed the strength of people power
But there are plenty of misconceptions about Pora.
Some see it as the youth wing of opposition leader Viktor Yushchenko's People's Strength (Syla Narodu) coalition.
Others think it is a newly-minted movement on the model of the Otpor and Kmara agitators in the Serbian and Georgian revolutions, often accompanying their analysis with baleful allegations of US government funding.
Foreign assistance that Pora is happy to acknowledge is the training given by Serbia's Otpor, now the Centre for Non-Violent Resistance, at seminars in Serbia and follow-up advice by Otpor veterans in Ukraine itself.
The association with Otpor and Kmara brought Pora international prominence, and clumsy government attempts to blacken it by association and even frame it for bomb attacks only gave the movement greater media attention.
Opposition leaders, including Mr Yushchenko, failed to maximise the potential of street agitation against the scandal-ridden administration of President Leonid Kuchma in the 2001 "Ukraine Without Kuchma" protests. That failure left relations strained between the radical youth movements and the constitutional opposition.
The youth movements saw the set-up in Ukraine as having allowed Soviet-era bureaucrats and the beneficiaries of dubious privatisation schemes to continue to dominate political life.
Pora has learnt from foreign non-violent protest movements
But they came to acknowledge after 2001 that street protests alone could not effect political change.
As the constitutional opposition began the slow process of coalescing around Mr Yushchenko - culminating in the founding of People's Strength and a shaky alliance with the Socialist Party - the youth movements began a similar consolidation.
From this Pora emerged in March 2004, with limited goals and a simple organisational structure, driven forward by the recruitment of young volunteer canvassers and the dissemination of information via its internet site.
It set itself the long-term aim of encouraging civil society and the rule of law in Ukraine, and the more immediate goal of ensuring free and fair presidential elections in the autumn of 2004. Fears of large-scale manipulation and falsification of the poll gave the movement focus.
Yushchenko says political enemies poisoned him
Pora eschewed a high-profile leadership and structured membership, in favour of local initiatives and central coordinators, relying on veterans of the earlier protests to recruit like-minded people.
Pora emphasised that it was not linked to any political movement and simply sought a fair election.
But the polarisation of society during the heated election campaign saw it associated willy-nilly in the public mind with Mr Yushchenko, who campaigned on a "clean government" platform.
US funding for non-governmental organisations in Ukraine has proved convenient propaganda for the authorities.
Congress and both the Republican and Democrat parties aid exit polls, pro-democracy funds and educational programmes, and it has been easy for government supporters to blur the distinction between these and groups like Pora.
The movement itself has always denied receiving US funding, and no evidence of it has been produced.
Pora is energetic, well-motivated and at ease with information technology, as one might expect from a movement dominated by young urban professionals. But it certainly cannot be described as slick.
Pora has clearly helped to galvanise the constitutional opposition. Its post-election vigils in central Kiev and provincial centres gave the opposition control of urban centres in most areas outside the east, without which it could not have gained political momentum.
Pora also gave the frustrations of young people a non-violent discipline and focus, without which they might have petered out in uncoordinated protests and worse.
It is however important not to overestimate Pora's impact.
Without the tacit agreement of many city councils and police restraint it would not have been able to build and maintain its tent cities.
Pora provided an impetus, but hundreds of thousands of people who took to the streets and camped out in freezing conditions to demand fair elections did so at their own initiative and not through a summons.
The failure of Zubr, Pora's sister-movement in Belarus, shows what happens when a youth movement tries non-violent resistance in a country with a more ruthless government and a less motivated public.
If Ukraine manages to elect a president in a free and fair election, Pora will have achieved its immediate goal. But its longer-term aim of fostering civil society will provide plenty of scope for its activists in future.
BBC Monitoring, based in Caversham in southern England, selects and translates information from radio, television, press, news agencies and the Internet from 150 countries in more than 70 languages.