Time Warner has just invested $12m in Social TV startup, Bluefin Labs, and another $12m in existing Social TV site, GetGlue. In the UK, Sky has just bought a stake in Anthony Rose's zeebox. Simple question: why?

The easy answer is that Time Warner, Sky and other investors in Social TV services think that they can make money in the medium to long term. But what's the business model here? How exactly do they believe they can capitalise and monetise the act of communal viewing? Here are 4 possibilities:

1.    Users & the new Television Land Grab

Headcount means a lot in and of itself. Just look at Facebook which, when it goes public (probably sometime later this year), is expected to be valued at around $100 billion based on 800 million members each individually prized (and priced) at $120. Social TV is a new frontier in the land grab of how television will be watched in the future. Investment = more money = more marketing = more users = bigger valuation. It's a sound strategy. As single-person households rise the theory is that more of us will want to immediately share our TV experience with close friends via Social TV apps instead of waiting till the next day to have water-cooler conversations.

2.    Advertising & Data-Gathering

Traditional advertising models for linear TV have always been about identifying a probable demographic that watches a show (e.g. 16 - 25 year olds tuning into 'The X-Factor') and targeting them with related advertising. It's, necessarily, an extrapolation. Similarly, BARB ratings in the UK are based on a panel of around 5,000 households. Social TV apps however have some distinct advantages.

First, because services like Zeebox and GetGlue allow for Facebook / Twitter sign-in, they can tell exactly who is watching what show and on what platform whether that's live or time-shifted. No guessing, just solid data and solid income. For advertisers - particularly online video advertisers - this is a real boon. Using a real-life example, one of the big online video advertising networks recently told me that 'The X-Factor' had a significant audience of 40-plus year old men that lived in Yorkshire who watched the show on-demand. Social TV apps can identify specifically and not just as a generalisation.

Second, BARB's sample is just way too small. The bigger Social TV apps, whilst they may not yet have truly caught the popular zeitgeist, are still used by more than 5,000 households. They provide real-time information about what's being watched where, when and by whom. What would you rely on? As a data tool, Social TV apps can give content-owners a much clearer indication of their expanded constituency.

3.    Shopping & Proprietary Technology

Some of the Social TV apps out there are fairly basic in that they incentivise users to participate with nothing more than the earning of 'badges' or community kudos. On the other hand, something like Zeebox, which uses distinct and proprietary technology, "knows" when an ad break is about to occur, "matches" a product displayed in a break and offers an online option to go and buy it. That's proper interactive shopping and is a cut above the rest of the field.

And if a Social TV app can incorporate "in-show" shopping ( as demonstrated by White Square Media), that really will be an innovation.

4.    More Content & The Long Tail

At the Smart TV Summit in London last November, Anthony Rose of Zeebox said that people wanted to know 3 things when they're watching a movie / TV programme: more information about the show itself, how to buy the things they see on-screen and how to see more episodes of the same show / series.

With Social TV apps you can easily access more episodes wherever they are on the web. This is the "long tail" - the idea that a digital asset (whatever it may be) has a much longer shelf-life than an analogue equivalent. For example, you may not have watched an episode of 'Blackadder' for years on linear television but you'll almost certainly be able to find it on the web somewhere.

And using this example, ('Blackadder' is on Lovefilm - sign up for a free trial. Lovefilm is NOT one of our sponsors!), users may be enticed to pay for more content and therefore provide affiliate income to the originating Social TV platform.