05/11/2013 10:13 GMT | Updated 23/01/2014 10:52 GMT

The Million Mask March by Anonymous

Today, at dozens of cities across the world, one million people will be marching. Many will be wearing Guy Fawkes masks, and protesting against...well it's not exactly clear. Injustice and corruption have both been mentioned. But internet spying by the NSA and other government agencies will be the main rallying call. It is being co-ordinated by the Anonymous movement, a loose collective of like-minded individuals around the world mainly concerned about protecting internet freedom and opposing surveillance.

It's hard to predict what will happen, or how many will show. But two things in particular are worth saying about all of this. First, Anonymous is one of a number of groups changing how politics is done: using the internet and social media to co-ordinate and organise offline actions. Anonymous was born on the popular US image board 4Chan partly as a joke: on 4Chan most people post under the username "Anonymous" so users can be free to post whatever they wish.

In 2008, some of them launched co-ordinated web attacks against the Church of Scientology, after the Church tried to remove videos of Tom Cruise giving a very bizarre interview. This was an affront to internet freedom and free access to information, the thing 4Chan users cherish above all (it was not the first time Scientologists had tried to censor content, either). Although it started online, supporters of Anonymous began to protest off-line too, co-ordinating hundreds of demonstrations outside Scientology centres around the world, using YouTube, Facebook and Twitter to mobilise and organise supporters.

The size, diversity and dynamism of social media platforms allow people to connect and form social movements outside the existing political channels far more quickly and easily than ever before. New social movements - often radically different in outlook and internal organisation - are emerging as a result, and challenging existing party politics in a way unthinkable a decade ago. The English Defence League in the UK; the Pirate Party in Germany, Beppe Grillo in Italy, and the Occupy movement are all examples of movements that have employed social media to grow rapidly and create a significant political and social impact - all in the last five years. This trend will continue.

Second, this march is notable for the diversity of groups that are likely to be involved. Five years ago, internet freedom was the preserve of internet aficionados like Anonymous and the Electronic Frontier Foundation. But that is changing, in part due to how central the internet has become to all of our lives, and part due to the revelations about how governments and businesses are accessing it, often without our consent. Defence of internet freedom now pulls in an extremely varied bunch.

The official announcement of the demonstrations called on 'Anonymous, WikiLeaks, The Pirate Party, Occupy and Oath Keepers to Unite Marchers, Occupiers, Whistleblowers and Hacktivists'. The Pirate Party was founded in Sweden to oppose intellectual property and create more participatory ways of doing politics - they now have a couple of MEPs who ally themselves with the Green Party. The Oath Keepers are a right wing libertarian group in American that asks soldiers to disobey any orders they believe are unconstitutional. Anonymous has always included in its ranks grey and black hat hackers who steal commercial and personal data and sell it. But they can all coalesce around the importance of Internet freedom. Surveys show it matters to the public too: a recent poll by the Pew Research Centre found 86 per cent have taken steps online to remove or mask their digital footprints. Other surveys consistently find that privacy online is of growing importance to citizens across world.

The date - Guy Fawkes Day - is of course intentional. The Guy Fawkes mask has always been the symbol of Anonymous, taken from the final scene in the movie 'V for Vendetta'. Guy Fawkes famously said 'a desperate disease requires a dangerous remedy' . They don't, as far as I know, plan to blow up the Houses of Parliament. But they do want to shake up the system. They won't give up easily in their efforts to defend Internet freedom. And they are growing in number.