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.