‘House of Cards’ viewer numbers, at least if tTwitter is any guide

ow many people watched the second season of “House of Cards” on Netflix? Only Netflix knows because the streaming service withholds viewership data in a way that Francis Underwood, the show’s conniving main character, might admire. But if the number of messages on Twitter about “House of Cards” is any clue, the audience for the political thriller may have grown substantially.

General Sentiment, a social analytics company, measured the volume of activity on Twitter related to the Season 1 and 2 debuts for The New York Times and found that over a similar 11-day period, there was a 430 percent increase in tweets about the show from 2013 to 2014. Last year, the firm recorded 254,460 tweets; this year, the number was 1,350,400. In fact, more tweets were written about “House of Cards” 10 days after its debut in 2014 than on the day of the series premiere in 2013.

Audience tweets are an imperfect proxy to calculate the number of people who viewed the series. Some people tweet about a show they have not yet watched, or do not intend to watch. But many users of the social network also share their impressions as they experience televised entertainment, and a surge in tweets about a show may indicate more people are tuned in.

When “House of Cards” began streaming on Feb. 1, 2013, it was relatively unknown, with few people thinking of Netflix as a place to turn for original entertainment. The total number of tweets about the show registered in the the low tens of thousands that day, and never grew much higher over the next 10 days.

But a very different picture emerges on Feb. 14, 2014, when Season 2 of “House of Cards” appeared. Compared with the activity on Feb. 1, 2013, nearly 10 times as many tweets were written about the thriller. While the activity leveled out, on Feb. 24 the volume was still higher than for the show’s debut in 2013.

Other proxies have also been used to get a better understanding of Netflix’s viewership for Season 2. Procera, a firm that works with broadband Internet providers, calculated that 5 to 15 percent of Netflix subscribers watched at least one episode of the second season on several broadband networks it did not name. Analysts at Citigroup used Google Trends to show a 76 percent increase in the number of searches related to “House of Cards” between 2013 and 2014, which they argued suggested an increase in viewership.

The season premiere of “House of Cards” may have driven a surge in Twitter activity, but the number of tweets for the most popular shows on broadcast and cable television is still much higher.

Nielsen SocialGuide, which measures Twitter activity around broadcast and cable TV programming released a report on Feb. 10 showing that about 1.2 million tweets were written about the midseason debut of AMC’s popular zombie thriller, “The Walking Dead.” That’s slightly fewer tweets than were written in total between Feb. 14 and Feb. 24 about “House of Cards.” And while “The Walking Dead” continues to drive high volumes of Twitter activity week after week, the surges in tweets about Netflix shows appear to trail off rapidly after they are added to the service.