Nielsen, the long-time leader in TV audience measurements, is taking their methodology online.

Today, the company announced a pilot program for the Nielsen Digital Program Ratings which will track TV content viewed online. The pilot starts with a handful of big-name partners – A+E, ABC, AOL, CBS, The CW, Discovery Communications, FOX, NBC and Univision. The pilot is set to begin in May and run through July, but Nielsen is already announcing that the Digital Program Ratings will see a commercial launch. The pilot program is simply serving to “fine-tune” Nielsen’s methods before they hit primetime, or, later streamed on the internet time – whatever.

“The pilot for Nielsen Digital Program Ratings is a major milestone for the industry,” said Eric Solomon, SVP for Global Digital Audience Measurement at Nielsen. “As a companion product to Nielsen Online Campaign Ratings, Nielsen Digital Program Ratings will enable clients to better understand the online audience for their programming by harnessing the same methodology Nielsen already uses to measure the audience for related advertising.”

Nielsen says that they will start by measuring TV content viewed online, on computers. For instance, CBS will be able to see Nielsen’s numbers for how many streams their online content got on their official site. During the pilot, initial results will only be shared with clients, but Nielsen hopes to make the data public when the program sees a full launch later this year.

Of course, Nielsen plans to expand the program to “additional content types and devices” in the future. So we’re talking streams from sites like Hulu or YouTube, made on and iPad or Xbox.

Nielsen already has an presence in online metrics, including web content (YouTube videos and such). They also track websites based on visitors. This pilot program marks their first foray into tracking online streams of traditional TV content, however.

“The potential to measure video viewing of specific programs on linear TV as well as the Internet is significant,” said Alan Wurtzel, President of Research and Media Development, NBCUniversal. “It’s an important step toward reaching the ‘holy grail’ of true cross-platform measurement.”

It’s an interesting move from Nielsen, but the online viewership tracking won’t really come into its true form until Nielsen is measuring all types of online TV streaming across all types of devices. Although Nielsen is just announcing this pilot program, it’s clear that full inclusion is what they envision.