Nielsen will soon begin to measure the television viewing behavior of people that watch content online as part of their new Digital Program Ratings. The pilot program kicks off in May and will run through July with participation from the following networks: A&E, ABC, AOL, CBS, The CW, Discovery, Fox, NBC and Univision.

Specifically, the networks that have signed up will allow Nielsen to track viewership of programs offered on their websites. For example, NBC will allow the company to gather usage data about people who stream shows from Networks will then be able to compare their internal stats with those from Nielsen to help refine the system.

Eric Solomon, SVP for Global Digital Audience Measurement at Nielsen said the pilot program is a major milestone for the industry as it will enable clients to better understand online audiences by harnessing the same methodology Nielsen uses to measure the audience for related advertising.

While it's a step in the right direction for Nielsen, the pilot program is still lacking in a number of categories. For example, it will be able to track viewing of television content from computers but not from tablets and smartphones - two outlets that are used frequently to view streaming content online.

Furthermore, the program can only provide web-oriented metrics like unique views and information about the age and gender of viewers. It still lacks metrics that Nielsen captures with traditional television viewers.

One of the main problems with online viewing, Solomon said, is there isn't a good way to measure how long a user tunes in to a particular stream. A broader commercial rollout is expected later this year, we're told.