Good news, fans of livetweeting: Nielsen and Twitter are creating a tool to show how you talk about your favorite shows. The downside: It might only be TV networks and advertisers who see what you’re saying.

The traditional Nielsen rating model of using a sample of households to measure what U.S. TV viewers are watching is outdated. Many people turn to their DVRs, online catch-up services like Hulu, torrents, or pirated streams to catch their favorite shows. This makes tracking what people are really watching a difficult prospect.

That’s where Twitter comes into play. With more than 140 million active Twitter users sending billions of tweets a week and TV networks increasingly displaying hashtags on screen, there’s inevitably a lot of talk about TV. Nielsen and Twitter are creating the Nielsen Twitter TV Rating, a ratings metric based solely on Twitter’s data.

Twitter’s head of media, Chloe Sladden, noted in a blog post that Twitter’s TV partners have long asked for a way to more easily see what shows people are tweeting about. The Nielsen Twitter TV Rating is intended to complement the traditional TV ratings system.

Nielsen said the system will boost the social TV stats from SocialGuide, which was acquired last month by NM Incite, a joint venture between Nielsen and McKinsey & Co. The Nielsen Twitter TV Rating will track not tweets about TV broadcasts, but will also look at those “who were exposed to the activity” (in other words, people who read tweets talking about shows).

There are a number of difficulties in tracking that conversation, especially since it’s not always easy to determine the context for tweets. Someone who’s watching Homeland could send a single tweet while it’s on the air (for instance “I can’t believe that just happened!!”), and it might not be noted as a relevant tweet.

On the other hand, this could prove a boon for shows that don’t always set the ratings chart alight, but have a cult following. It’s not exactly like Community is a huge hit, for instance, but it
has a large online fanbase.

Sladden added that Twitter’s ultimate aim for the tool is “to make watching TV with Twitter even better for you, the TV fan.” Details are scant on how that might work, but if it helps quality shows which are underserved by the Nielsen system gain more attention, that cannot be a bad thing.

Photo via tvgirl17/YouTube