Founded in Sweden six years ago by a group of Internet freedom activists, the Pirate Party has since been spreading across the globe at mind-boggling speed.
The Pirates, whose core agenda is to increase people's privacy on the Internet and protect freedom of speech, are now active in more than 50 countries, from Europe to Australia, Belarus, Nepal, and Tunisia.
In Germany, they have seats in two regional parliaments -- Berlin and Saarland -- and are expected to take about 13 percent of ballots in the 2013 legislative elections, vying with the Greens for third place.
Their Austrian counterparts made their electoral debut this month by winning a municipal seat at local polls in Innsbruck.
The original Swedish version of the party, Piratpartiet, even has two deputies in the European Parliament.
Accounting for much of the Pirates' spectacular rise, supporters say, is the lack of political debate on moral issues raised by the development of new technologies.
Swedish Pirate Party head Anna Troberg
"It's a completely new world around us, everything is digitalized, and this affects people's private lives and work," says Piratpartiet's leader, Anna Troberg.
"It means people are increasingly interested in these issues and are looking more closely into how this technology can be both used and abused."
In this respect, the Pirate parties fill a gap keenly felt by many Internet-savvy voters, or, as Troberg puts it: "The Pirate Party tries to answer questions that the old parties don't even realize they have to ask."
Supporters have also praised the party for taking a refreshingly down-to-earth approach to politics.
While some of their goals are clearly utopian -- like free public transport, for instance -- their calls for greater political transparency and equal access to culture and information have struck a chord with people increasingly disillusioned with traditional political parties.
Pirate parties share the conviction that ordinary citizens are entitled to a greater role in decision-making.
Instead of holding discussions behind closed doors, they stream their debates and meetings online.
In Berlin, the party has even developed a software system, Liquidfeedback, allowing anyone to suggest new policies.
Since their creation in 2006, the Pirates have expanded their initial focus on digital freedoms to include "offline" civil rights and social issues.
And in an effort to show that their financial policies and behavior are as egalitarian as their agenda, they favor casual wear and hold party retreats at youth hostels or other low-key venues.
Member of the European Parliament Marietje Schaake
"Voting for a Pirate party is also a protest vote, but in a more positive way than voting for the populist far-right, which is also a voice against the establishment," says Marietje Schaake, a European Parliament deputy who has actively worked on digital-rights issues.
"[The Pirate parties'] popularity is a reflection of the fact that people don't feel represented by a lot of the mainstream parties anymore and that democratic political parties face legitimacy issues.
"We are seeing several manifestations of a shakeup of our political landscape as we know it, and this is one of them."
The Pirates' belief that culture and knowledge should be shared free of charge appeals to a large portion of what Troberg describes as "the generation that grew up with [the] Internet."
The bulk of followers are between 15 and 30 years old. Troberg, who is 38, says many are first-time voters.
The Pirates' staunch opposition to the Anti-Counterfeiting Trade Agreement (ACTA), an international treaty to establish standards for intellectual property rights enforcement, has also galvanized support for their parties.
They advocate a reform of copyright laws, with entirely free noncommercial copying and a five-year copyright for commercial use.
They also call for the abolition of pharmaceutical patents, which they blame for killing people daily in third-world countries.
Critics dismiss the party's program as unrealistic and potentially harmful.
"There are a lot of business copyrights where five years wouldn't have too much of a significant impact," says Susan Singleton, a British lawyer specializing in intellectual property issues. "However, [there are] an awful lot of other copyrights out there -- films, books, plays -- where people don't make very much money from their rights.
"It takes a lot of years to recoup your investment, and people might stop investing in copyright works if they aren't going to get any kind of financial reward from it."
Detractors also point to the apparent contradiction between the Pirates' campaign to step up online privacy while promoting the free flow on information on the web.
A delegate wears a sweatshirt with the Pirate Parties International (PPI) logo during their international conference in Prague earlier this month.
Troberg, however, maintains that the Pirates are perfectly aware of this paradox.
"Those two things are in conflict, very often," she says. "Our work is to find where these things clash and where it's best to put the dividing line. As a general rule, we advocate privacy for individuals but transparency for governments and government agents."
'The Sky's The Limit'
The Pirate parties' exponential growth is likely to gather steam as supporters stop worrying that a vote for them would be useless.
Their technological know-how also puts them at an advantage over older, bulkier parties by allowing them to deploy electoral campaigns in record time with limited financial resources.
But as the Pirates secure their foothold in politics, Shaake says they will have to strike a fine balance between their new duties and the ideals they were elected on.
"Can they live up to the promise of being an alternative and really challenging the establishment now that they have responsibility?" she asks. "That's always a question for newcomers on the political stage."
For now, the Pirates' ambitions are growing as fast as their numbers.
They are planning to dramatically increase their presence in the European Parliament.
At their international congress in Prague last week, they agreed to campaign as one bloc in the parliament's 2014 elections.
Discussions to set up parties are under way in a number of new countries, including China, a one-party state that doesn't have free elections.
"The sky's the limit; if we work hard we can go as far as we want to go," says Troberg. "It also depends on the other parties; if they start moving along our lines maybe fewer people will go to the Pirate Party.
"But it doesn't matter, because it's not the party as such that is important, it's the issues we are working on."