This weekend, thousands of activists decked themselves in purple ribbons and marched through the streets of London, Edinburgh, Newcastle, Oxford and York to demand a change to the British voting system. Large numbers of them had been mobilised through Facebook.
"One of the most prized assets in politics is how many people you can put on the streets or in a room," said Guy Aitchison, organiser of the exuberant Take Back Parliament protest. "Facebook allows campaigns to connect to large numbers of people in a short space of time, meaning that it's easy to organise demonstrations at short notice."
Twenty-three million Britons have Facebook accounts, and the site's organisation of personal profiles and public pages allows citizens, activists, politicians and media pundits to network and share ideas with a semblance of immediate humanity that paper petitions and dry email lists will never capture.
But alongside the obligation to sign over personal data to unknown third parties, campaigns on Facebook are circumscribed by private control of the terms and scope of public debate. The energy and efficiency of Facebook campaigns come with a price.
Given its importance to our lives as a gossip channel, public CV archive, photo album and social calendar, it's easy to forget that Facebook is not an open forum, but a privately owned space. Last week, the University of London Union president, Clare Solomon, had her personal account disabled after setting up the protest group "Can't pay, won't pay: solidarity with the people of Greece".
Other administrators of the group were also banned from the site, and when Solomon attempted to set up a new profile, it vanished within minutes.
"My disappearance concerned my family and friends," said Solomon. "I use Facebook for work and for communicating with activists all over the world who I might not have been able to meet otherwise. Having my account disabled was really inconvenient -- and disconcerting."
Speaking for the public
The US campaigns group Racebending was also banned from Facebook this week, after the group's attempts to raise awareness of how Hollywood casts white actors to play characters of colour were deemed "hateful, threatening or obscene" by site censors.
"The page had almost 6,000 members, and was a key way for us to keep in touch with most of our supporters," said a spokesperson for Racebending. Beneath Facebook's placid navy-blue surface of thrown sheep and targeted advertising widgets are intricate strata of digital control, overseen by a private company that has no official responsibility to provide users with an objective place to organise.
"Facebook seems like a giant blackboard where people can write whatever they want, but actually it's privately owned. Nobody has an automatic right to express themselves, and the company is entitled to rub out anything it wants to rub out," explains Kate, an IT systems administrator.
"Alongside those who don't use the internet at all, there are plenty of technologically minded people, like myself, who are concerned enough about the security of their data not to get involved. It can seem like Facebook represents public opinion, but it doesn't."
Only two-fifths of the UK are regular Facebook users. That you're reading an article on the New Statesman website means that it's likely you're one of them, but contemporary politics is not owned solely by those of us who've filled out the "favourite quotes" section.
While digital activism is constantly creating new, exciting arenas for political involvement, we must be careful not to ascribe too singular an importance to Facebook as a political barometer or organising space.
"Having my account disabled brought home the fact that Facebook is a service run for profit and controlled by those who own it." said Solomon. "We contribute content, and then the company makes money by using our free labour to boost advertising rates.
"I'm planning to transfer myself and my friends over to an open-source software model, where we will have more control."
Facebook is the first click for media outlets wishing to read the writing on the world's playground wall, where undercurrents of political sentiment jostle for space among crude smiley faces and time-worn crushes.
What can seem like the voice of the people is in fact a restricted private channel, compromised by commercial interests. Facebook remains a superlative organising tool, but its relationship to the political zeitgeist is far from simple. In fact, it's complicated.
Laurie Penny is a writer, journalist and feminist activist from London. Her blog, Penny Red, was nominated for this year's Orwell Prize. Her first book will be published later this year by Zero.