There's a Facebook feature that could sway voting in the EU referendum. The power of the site's "voter megaphone" could influence the result of a very tight race, as young people - traditionally non-voters - encourage one another to get involved.
Plenty of politicians used to dismiss social media as unimportant (Cameron himself, in fact) but now they're all getting on board. There are #ask Q&As on Twitter and Facebook, campaign photography on Instagram, endless videos of hustings on YouTube.
Brands have known the power of social media for years. But then, politicians have always been behind the curve.
At first I saw just one young person wearing a red T-shirt with the rose symbol of the Labour party. Clutching a clipboard, she moved deftly from one terraced house to the next in suburban south London. Further down the road, I saw a clutch of them: canvassers. I was late for a train but wanted to shout: “I’m a voter — convince me of something!” My first vote was for this month’s London Assembly and mayoral elections. Keen to share the joy of my enfranchisement, I tweeted about it. Only later did I realize I could have used Facebook’s “voter megaphone” feature. This reminds people to go and vote on election day with a notification when they log into the site. There is also an “I’m a voter” button that displays to friends that you have voted.