Has media measurement company Nielsen created the tool that will help monetize online television?

We won't know for awhile, but if Nielsen's "Internet Meter" for measuring online TV audiences proves reliable, it will eliminate much of the mystery regarding metrics for the fast-emerging viewing platform.

As Sarah Perez explains over at ReadWriteWeb, "Until now, this ever-increasing demographic has been left out of U.S. television ratings as Nielsen currently focuses only on live and time-shifted (i.e. DVR) TV viewings." She adds:

This new addition to the ratings game is bound to have a major impact on TV monetization efforts as both networks and advertisers will see, officially, how many viewers have tuned in to watch this "2nd screen."

In the announcement on its web site, Nielsen executive Sara Erichson said the Internet Meter software is installed in 375 U.S. homes as part of Nielsen's National People Meter panel, "allowing us to evaluate the measurement of Internet usage alongside TV usage."

The results of our evaluation show tremendous promise to date. We are positioned to start the roll out of the Internet meter to all People Meter households before the end of this year, with complete installation in 2010 and full implementation in early 2011.

Perez writes that the Nielsen data "will reveal a plethora of information regarding not just viewing numbers but also the demographics of who watches what and when."

The information can then be used by advertisers and marketers who want to target niche audiences like the hip crowd who watches sci-fi shows but never stays home on Fridays to view them live on TV when they air. Or the group of people who are too embarrassed to set their DVRs to record "Ugly Betty," but sneak in the guilty pleasure online in their free time. Expect the online ads interspersed with the online content to soon become more precise and more targeted than they are now, thanks to these sorts of reveals. Perhaps the networks will even be able to charge more for ads, once they have numbers to back them up. That would be a good thing for the industry as a whole as well as consumers, since it could lead to more shows being put online.

Nielsen recently reported that time spent watching video online increased nearly 50 percent in the second quarter from the previous year.