Who has won the social referendum?

Facebook is introducing a function allowing Scots to show they have voted

It was the 2008 Obama presidential campaign that first showed how politicians could use social media as a campaigning tool. Now the Scottish referendum could prove another landmark in the influence of the likes of Facebook and Twitter on debate.

Millions on both sides have taken to tweeting and Facebooking their views on the issues. But never mind who wins the referendum - who has come out on top in the social media battle?

This morning Twitter has released figures showing the surge in interest over the past month. Over the past year, there have been 5.4 million tweets using the #indyref hashtag, but 2.3 million of those were sent in the past 30 days.

Facebook, on the other hand, saw 10 million of what it calls interactions - posts, comments and likes - about the referendum over the past month. So if the two currencies are comparable - a big if - then four times as many people are discussing the campaign on Facebook as on Twitter.

But when it comes to direct engagement, with one side or the other, things look more equal. In the past 30 days there've been something like 232,000 uses of the Twitter #bettertogether and #nothanks hashtags, while more than 750,000 tweets have used #YesScotland and #VoteYes.

And tweeting activity has surged during the debates, with 186,267 in the first, rising to 255,559 in the second.

Meanwhile, on Facebook the Yes campaign's page has attracted 258,000 likes compared with 182,000 for the No page. When it comes to the volume of conversation Facebook says the two sides are neck and neck, but the recent momentum is with the Yes campaign.

But what can we know of the depth of engagement on each network? It certainly feels as though Twitter is a public arena where people go to see what is happening and give their own instant analysis of events, whereas Facebook is a more private and personal place where friends debate the issues.

I've certainly seen more bad tempered abuse on Twitter, where flame wars seem to bubble up between vocal supporters of each side. Facebook is a bit more tranquil, with friends pointing out where each other is wrong more in sorrow than in anger. Or perhaps that is just a reflection of my own networks...

Which then is the more useful to the campaigns? Twitter seems far more visible, and has become the instant campaign news agency for journalists and politicos. But I would guess that Facebook is more influential - it has a much bigger audience and one status update from a friend backing a campaign must be worth any number of tweets from a politician.

What we should not do is assume that the weight of feeling on Twitter or Facebook is an indicator of the result. During the last UK General Election any number of so-called sentiment analysis experts chewed through social networking data to make forecasts. Most proved far too optimistic about the proportion of the population that would support the Liberal Democrats. Every political campaign now needs a social media strategy - but if you want to know which way the votes will fall, you are probably better off asking a bookie.