OpenTV will open up its TV measurement platform to third parties, which it hopes will developers will embrace for next-generation set-top boxes that track detailed information about viewers’ behavior, it said on Tuesday.

Open TV’s platform makes it easier for operators to gather detailed data on what programs and ads viewers watch and for how long. The necessary data formats will be released later this year, OpenTV said in a statement.

Operators will be able to measure the usage of personal video recording, video-on-demand and interactive applications. They can also generate new revenue from advertisers by selling ad viewership reports, down to second-by-second measurements of how long subscribers watch an ad before changing the channel or fast forwarding.

This kind of detailed information on the activity of viewers can make TV and advertising more relevant, but it does open up privacy questions.

“It’s a very tricky subject, because as a customer you don’t want the operator to know everything you do,” said Jens Häger, media analyst at market research company Mediavision.

If the operators want to use the technology, they will have to very open with how they are using it and get proper consent from subscribers, according to Häger. It will be easier to get subscribers to accept its use for tailor-made programming, but perhaps harder to get subscribers to consent to having information passed to advertisers, he said.

OpenTV is aware of the privacy implications of its platform. The system allows collected data to be anonymized or filtered according to privacy rules, the company said.

OpenTV’s software is used on 133 million devices worldwide, and is used to offer program guides, video, recording and tailor-made advertising, according to the company. Partners include Motorola and Cisco, and its customer list includes Time Warner Cable in the U.S. and BSkyB in the U.K.