For years, last night’s television has sat alongside the weather as a key element of social currency — the sort of thing that we will talk about around the water cooler.

The growth of social media means that these conversations aren't just happening after the events, but are now happening around the content, and have become much more visible.

If you are a Twitter user, then you are probably familiar with the phenomenon — whether it is tweeting along with "event TV, or simply watching the streams of conversation as a supplementary form of entertainment.

At SMG, we are interested in what this can tell us about the ways different audiences are engaging with different types of programmes, so we have been looking at the top TV programmes (according to BARB's figures) and, using Sysomos’ Social Media analytics tool, analysing both numbers of mentions and the level of online conversations going on around them.

By combining the levels of online conversation with TV audience sizes, we have created a "Social Media Score" for TV programmes. This gives us an indication of levels of audience engagement in the broader conversations surrounding the show.

BBC lead for Christmas week…

For the Christmas week, this is what we saw around the top TV programmes, with Eastenders showing the both the greatest level of activity, and also the highest Social Media Score (which takes its larger audience size into account. With an average of 1,000 tweets per minute, the Christmas Special was clearly taking the conversations beyond the limited reach of the family living rooms.

Source: BARB, Sysomos, SMG Research

Even though Eastenders and Downton Abbey’s Christmas Day specials were screened at the same time to similar sized audiences, the way those audiences were interacting online were quite different. This backs up what we see about their audiences elsewhere, as Twitter users are more than three times as likely to “specially choose to watch” Eastenders than Downton Abbey (source: TGI survey, Q4 2011)

But the key difference between the two shows becomes more apparent when looking beyond the Christmas special itself — the Downton Abbey series finale in November actually generated more Twitter conversation than the Christmas special, while the Eastenders Christmas special generated about six times as much online conversation as a typical episode. (Conversely, Emmerdale’s Christmas Special failed to generate much online talk, despite a massive peak earlier in the month as Cain’s “Judgement Day” storyline reached its climax.)

Next in the table is Sherlock, generating twice as much conversation as Doctor Who – despite seeing a significant level of catch up viewers who would have missed the chance to join the conversation (who apparently helped to set a record for iPlayer viewing the next day.) (source: Hitwise blog: http://weblogs.hitwise.com/robin-goad/2012/01/sherlock_sets_new_record_for_b.html)

But while large audiences certainly help to fuel large conversations, our metric can also help to identify the smaller audiences who are more highly engaged online with conversations around the programmes. So while Channel 4 might not have made an impact on the top ratings, the Big Fat Quiz of the Year’s 4.35 million viewers generated a lot of online conversation, earning it a Social Media Score of 9.0- more than all but two of the top 10 rated shows.

… But ITV charge into the New Year!

Although the Christmas Eastenders episode topped our social charts, the New Years episode was far less dramatic, with less than a tenth of the amount of online conversation.

Without the Christmas specials to compete with, Sherlock moved up the ratings table despite a slightly smaller audience for the second episode of the series. But only a slight dip in the levels of conversation around the programme earned it a Social Media Score of 12.8 — down from 14 for the New Years Day episode, but taking it to the top of the top 10 programmes by audience size.

But the key point that larger audiences aren't necessary to achieve greater levels of online conversation was echoed again, as "Take Me Out" returned to ITV for a third series. Despite an audience of less than half of the Eastenders Christmas special, it generated more online activity with almost 75,000 tweets about the programme, reflecting in a Social media Score of 53.8 - our highest reported score yet. Although the level of conversation peaked during the show itself, there were significant mentions of the show both the day before and the day after the show itself, showing a level of ongoing converation around the show. Again, the conversations weren't just limited to the time — or even day — of broadcast, but were ongoing throughout the week.

The final episode of the series of Sherlock might not have grown the audience, but the level of activity went through the roof with nearly 100,000 tweets on the day of the broadcast and almost as many again over the course of the week, earning it a Social Media Score of 33.3.

The second episode of Take Me Out saw a slightly smaller audience as well as slightly less conversation around the show. However, it would appear that the faithful tweeters were in the remaining audience, as the Social Media Scoring went up to 34.3.

What do we learn about the audiences?

Obviously, a quantitative metric like this doesn't account for a number of factors that might affect the levels of online conversation. Does a programme have a strong storyline, or characters who give the audience something to talk about? Is the show promoting a hashtag on-screen to encourage viewer involvement, or running an official Twitter account to provide additional stimulus for conversation? These are things that we plan to investigate in due course — but in the meantime, some interesting factors are emerging from the numbers. For example, looking at the types of audiences that lead to higher levels of conversations, it would be fairly predictable to say that shows with a larger younger audience would have a greater level of online chatter around them, but we are starting to see patterns that suggest that it isn't just the size of the younger audience, but rather the general profile of the audience that correlates best to the volume of conversation.