I suspect that video-on-demand will contribute significantly to Nielsen's obsolecence (as if there aren't enough other really good reasons for that to occur in the television ratings game).

This week, Nielsen told clients that it will start measuring VOD viewing beginning second quarter 2006. The phased-in approach will begin by rating "recently aired television programs," i.e. those programs watched within seven days of their airing on "regular, linear television." By the fourth quarter 2006, Nielsen will start rating "library product," which it defines as theatrical movies, PPV events, and older TV shows.

Phase one essentially insures that clients are getting credit for time-shifted viewing of their current programming.

Initially, VOD viewing will be combined with other playback ratings, such as from a DVR. But beginning in fourth-quarter 2006, the VOD number can be broken out, though that will require cable MSO's, TV networks and stations to cooperate to make sure that a VOD "flag" is inserted in order to "isolate" the VOD viewing. Nielsen pledges to have the technology in place to recognize that flag.

Saying it realizes most VOD is not recently aired regular TV, phase three, also beginning in fourth quarter 2006, means Nielsen will start measuring library product--like HBO movies--which will require embedding a code in each show, since it will lack the Nielsen codes on already-aired fare.

You can read the whole article at Broadcasting & Cable.