The fact that the Pirate party has won 8.9% of the vote in the Berlin state elections – thereby giving them 15 seats in the legislature – has given rise to some head-scratching in psephological circles. And not without reason: it isn't often that a political party takes a relaxed view of filesharing, advocates radical reform of intellectual property laws, opposes state surveillance in all its forms, evangelises about open source and then has electoral success in the real world.

The big questions are: is the Pirates' electoral success a culturally specific blip, or a pointer to longer-term political change? Have we reached the point where the internet is having a measurable effect not just on political discourse, but also on what happens in polling booths? And could it happen here?

The answer partly depends on which electoral system we're talking about. Germany has a strictly proportional system: once a party receives more than 5% of the vote it becomes eligible not just to hold parliamentary seats, but also to receive state financial support. So vocal minority parties that can persuade more than 5% of the electorate to turn out can expect to have a political impact. That's why green parties have done relatively better in Germany and Ireland than they have in other jurisdictions. (The last – discredited – Irish government, for example, was sustained in power by an alliance between Fianna Fáil and the tiny Green party.)

So what happened in Berlin definitely couldn't happen here. If you doubt that, just ask the Lib Dems, whose share of the popular vote never translates into an equivalent number of parliamentary seats.

There's also a cultural dimension to this. Historically, Germany has been the European country that has been most receptive to, and enthusiastic about, open source software. The Bundestag is one of the few legislatures in the world where you can find deputies who are knowledgeable about Linux and free software generally.

The German government was one of the first to decide that national-security systems should not be based on proprietary software. In such a climate it's predictable that a campaigning political party with a radical online agenda would find a ready audience. The bovine way in which the last House of Commons passed Lord Mandelson's digital economy bill, with its clueless 'anti-piracy' provisions, does not exactly engender confidence in the British political class's understanding of these matters.

The great puzzle of the last decade is why the burgeoning of online political discourse doesn't seem to have had a proportional impact on the ground. The test case here is Barack Obama's presidential campaign, which was positively inspired in its use of social networking and other online tools. His election led some enthusiasts to believe that he would be able to mobilise this vast online movement to bypass Washington's dysfunctional legislature and achieve meaningful social and economic reform. It didn't happen: as president, Obama didn't choose that route; and even if he had it's not clear that it would have had that much impact in terms of achieving real reform.

Online activism seems to be good at getting people motivated and worked up for short-term campaigns – as the Tea Party has shown. We haven't yet discovered how to use it creatively as a tool for improving governance.

Is there anything established political parties can learn from the Pirates' success in Berlin? Yes, if they are operating in political jurisdictions with electoral systems based on proportional representation. The lesson there is that there is a small but significant segment of the electorate – mostly young, and mostly apathetic about conventional politics, but very interested in filesharing, social networking and other online activities – whom it would be unwise to ignore. But British parliamentarians, secure behind an unfair but immovable electoral system, can sleep easy in their beds.