Comcast Corp. and Time Warner have pacted to amp up Comcast’s Xfinity broadband video service with more programming just as the TV biz is poised to begin capturing ratings — and more advertising dollars — from online viewing of full-length TV shows.

The long-term deal will make significantly more shows from the Turner Entertainment realm available to Comcast subscribers via Xfinity, and it calls for the two to experiment with live real-time streaming of CNN and possibly other programming. It also covers Turner-branded iPad, iPhone and Android-based tablet and phone applications.

The Turner shows that run on Xfinity carry the exact same advertising spots that the episodes carry in a traditional TV telecast. That uniformity will allow Nielsen to measure viewership of those shows on Xfinity, and then cume those numbers with ratings derived from live viewing and DVR viewing done within three days of the original telecast.

The TV biz has been pushing Nielsen for more than a year to find a way to deliver an omnibus ratings stat for shows that combines TV, DVR and online platforms — rather than having to sell online ads based on a separate measurement stat. Nielsen is poised to launch its “three screen” ratings by the end of April.

“It helps us close the loop on how to create a monetizable model for the digital world,” said Jack Wakshlag, chief research officer for Turner Broadcasting. “It’s an important opportunity that really extends our content into more new platforms. With (ratings) measurement in place, we think distributors will have more confidence in making TV Everywhere (services) part of their distribution plan.”

Comcast, the cable giant that just swallowed up NBC Universal, and Time Warner were the pioneers of what the partners dubbed “TV Everywhere” services, offering broadband access to cable programs to viewers who already have cable, satellite or telco subscriptions. It was a response for consumer demand for more flexibility in viewing shows on their own timetables and on mobile devices.

It was also a 180-degree turn from the Hulu model of making broadcast TV shows available for free with embedded advertising, albeit not nearly the same amount of spots as would run in a regular TV telecast. Hulu has been a hit with viewers but not a cash cow of advertising revenue for its partners, NBC U, News Corp. and Disney. There is increasing speculation that Hulu is moving toward an all-subscription model, following the launch last year of its $10 a month “Hulu Plus” service. (Comcast, as part of securing regulatory approval for the NBC U merger, was forced to give up NBC U’s management rights in Hulu.)

With the TV Everywhere model, viewers have online on-demand access to programming so long as they remain paying cable, satellite or telco customers. (TV Everywhere was a generic term given to the concept of subscribers using an authenticated password for online access to programming; operators have different names for their proprietary services, i.e. Comcast’s Xfinity.)

Comcast launched its Xfinity service in late 2009, with a smattering of Time Warner-owned shows. The new deal covers an expanded slate of shows from Turner cablers, including TNT’s “The Closer,” “Men of a Certain Age” and “Southland,” TBS talkers “Conan” and “Lopez Tonight” and CNN’s “Piers Morgan Tonight,” among many other shows from Cartoon Network, Adult Swim, TCM and other nets.

“When we first announced the TV Everywhere initiative with Comcast and (CEO) Brian Roberts 18 months ago, it was an untested idea facing technical doubts and competitive pressures — but already more than 50 million consumers can experience some form of it from a wide range of content providers and distributors,” Bewkes said.

Comcast is in talks with a range of other distributors to expand the programming served up to Xfinity. The promise of being able to roll up online ratings into traditional TV ratings will be a big carrot to get more programmers on board. Among broadcasters, the CW has been prepping for the new era of three-screen ratings by making its shows available online with the same commercial spots as run on TV.

“The computer now becomes a just another TV screen. The (online) ratings will become part of the regular data stream,” Wakshlag said. “If you’re watching (a program) within three days of its premiere, it will count.”