Traditionally, TV networks gauge the number and demographic makeup of their shows' audiences by measuring the TV viewing habits of a small sample of households. Because the advertisers who pay for the shows and the networks who program them need an independent pollster both groups can trust, they've traditionally turned to Nielsen. But as TV audiences have shifted their consumption online, through apps and the web, Nielsen's audience-measuring methods have had to adjust. Other companies have tried to provide alternate metrics, but Nielsen is who the industry has relied on as its standard. And because Nielsen still has the best access to traditional TV viewing, it's been in the best position to provide new, cross-platform metrics to chart a program's audience across television, apps, and the web. After plenty of experimentation, this is what Nielsen has done — and maybe more importantly, what it's successfully convinced all the major stakeholders it can do.

One advertiser, one audience guarantee for all platforms and devices

Now, with ABC and Disney's networks ABC Family and ESPN, we have our first campaigns to use Nielsen's data to sell a TV program to advertisers across platforms. According to a Nielsen spokesperson, all three Disney networks are already using Nielsen's Online Campaign Ratings to sell ad inventory. Importantly, this isn't just just regular TV advertising sweetened with a little bit of data from the web. ABC is making the biggest leap: its "ABC Unified" campaign sells programs to advertisers across all platforms, from TVs to computers, tablets, and smartphones. One ad buy, one "audience guarantee" — a breakdown of a show's total audience combined across all of those platforms. ESPN is doing something similar but more limited, working on cross-platform ad buys with just a few advertising partners, while ABC Family is using Nielsen's data to sell online video. (Last year, the CW became the first TV network to use Nielsen's data to sell ad inventory for online video.)

This will change which shows stay on the air and where they are seen

These changes in viewer metrics and ad buys matter because the ads and data about who they're reaching determine which shows stay on the air and which don't. Before, if a show like Community had a devoted online following but a small traditional audience, NBC had relatively limited ways to capture that and advertisers had little reason to trust NBC's data. Now, in theory, everyone has a better picture of a show's true reach.

More importantly, from a technology and platform perspective, how ads are purchased and displayed affects not just what shows get chosen, but where they are shown. If a show's audience is measured and ads are sold in a single buy across all platforms, that creates a tremendous incentive for a network to maximize the number of platforms where its shows are available. It also makes it more likely that networks will push toward parity across those platforms. It no longer makes sense to have some TV shows or episodes available on the web but not others, or to support streaming for the iPad but not the Apple TV. Measuring a show's viewership on the Xbox means more TV will come to the Xbox; measuring a show's viewership on over-the-top services like Intel Media means more programmers will be comfortable with TV delivered over the internet; measuring a show's viewership on smartphones means more shows will come to more smartphones. Nielsen still has a ways to go to before it can measure audience in those settings as well as on a television set or a desktop browser, but that's clearly the direction it's headed.

Measuring a show's viewership on smartphones means more shows will come to more smartphones

Finally, Disney's embrace of unified online and offline ad buys for ABC and its sister networks bodes well for one vision of Hulu. Disney and News Corp.'s Fox are reportedly weighing the fate of the joint streaming video venture, with all signs pointing toward one of the media giants buying out the other, while retaining Comcast's NBC as a minority partner. News Corp. and Fox have always preferred a more restrained approach to video streaming, withholding many of its shows and episodes and throwing its weight behind Hulu Plus' subscription model. Disney and ABC, on the other hand, have consistently embraced advertising as a primary revenue stream, both on Hulu and on its networks' own sites. (ABC and Hulu representatives were unable to respond to requests for comment.)

Will Hulu become more like Disney, or will Disney become more like Hulu?

If Disney ultimately takes control of Hulu, the service is virtually guaranteed to become more open. Nielsen data for advertisers could finally make paid subscriptions no longer necessary for viewing on non-PC devices. More Disney content from ESPN, ABC Family, and elsewhere in the broader kingdom will likely be made available. And if Hulu goes in the other direction, toward Fox and paid subscriptions, Disney will be well-positioned to create an ad-supported streaming alternative — first for its own content and catalog, but possibly for other networks' and online original series as well.

That's the move. It may be the only way out of the sluggish, half-hearted approach we've had for ad-supported TV on post-PC devices, from mobile to the living room: embrace the multi-device future completely, measure everything, and align everyone's incentives around new standards to keep the revenue pump primed. For the most part, it's how television has always worked. If Nielsen's and Disney's bets pay off, it's how most television will work in the future.