The Pirate Party is a strange beast that has no political analog in the United States, but there are other parties with the same name and same platform in Europe, where the "Pirate movement" advocates for copyright reform and an open Internet. (The first Pirate Party grew out of a Swedish think tank that also developed the infamous file-sharing website The Pirate Bay.)
These parties are generally progressive-leaning, but they intentionally eschew the traditional left-right political labels. Instead, they focus on civil liberty issues such as free speech, direct democracy, individual privacy, government transparency, and the open exchange of information and digital data.
However, their policies in other areas lean more toward egalitarian social democracy than neo-liberalism. They support market economics, but with a strong social safety net, universal health care, and high taxes to pay for services—the sort of governance you typically find in Nordic nations. Most provocatively, the Icelandic branch advocates granting NSA whistleblower Edward Snowden citizenship so that he may seek asylum in Iceland.
Typically seen as a party protesting copyright laws, national security policies, and the surveillance state, Pirate Parties have never before gained this much support anywhere. When Iceland's Pirate Party took five percent in the 2013 elections, giving them three seats, that was the best result such a party had ever received for a national parliament. Recent anti-government protests over secret E.U. negotiations seem to have bolstered the party's appeal based on their advocacy of transparency, but that alone doesn't begin to explain much of their appeal.
Iceland uses proportional representation, with voters voting for their favorite party, not individual candidates, so parties generally win a number of seats equivalent to their percentage of the popular vote. This could result in the Pirates having an enormous amount of influence if they do indeed take over 30 percent of the vote—though that is a very, very big if. In the same way that third parties almost always poll above their eventual share of the vote in the U.S., the Pirate Party may well revert to its typical role as a haven for protest votes.
Yet even though Iceland is a tiny country, if just one nation changes its copyright laws and tries to fight the international copyright regime, it could have significant consequences given the ways that the Internet has worn down national borders. This election isn't until April of 2017 at the latest, but this is still one of the most astoundingly unexpected poll results we've ever seen.