Are we one step closer to finding out how many people really watch House of Cards on Netflix?

According to the Wall Street Journal, for several months Nielsen has been tracking almost 1000 shows on Netflix, Amazon Prime and Hulu, finding out not just how many people are watching, but also data like viewers' age and gender.

This could be a significant step forward: Netflix and Amazon are able to gather very precise information on shows' popularity and subscriber viewing habits, but because they rely on subscriptions rather than advertising, there is no need for them to make this information public.

Meanwhile, everyone else is intrigued to know how original streaming shows like House of Cards and Ripper Street compare to TV shows on 'traditional' channels.

Jeremy Clarkson's move to Amazon and David Tennant's upcoming Netflix sci-fi drama show just how much these services are willing to invest in original programming – but whether that money buys big audiences is still a mystery.

Just this month Piers Morgan predicted that Clarkson's new motoring show "won't have a big audience in this country," while House of Cards showrunner Beau Willimon has said that even he doesn't know how many people have actually watched his show on Netflix.

Amazon earlier this month took the surprise decision to reveal its most-watched TV series on Amazon Prime UK in 2015. That accolade goes to fantasy drama Outlander – made by US cable channel Starz.

Unfortunately, the data Nielsen is collecting is still pretty limited. The report explains that they are only tracking viewers in the USA, and doesn't include views on mobile devices. The company says it is working to fill that big information black hole, but Netflix claim that not taking into account overseas and mobile subscribers makes the results meaningless.

Still some work to do then, before we discover whether Kevin Spacey is anywhere near as popular as Mary Berry.