The Register | September 3, 2006

The first thing that came out of our mouths when we heard that Google is working on a system that listens to what's on your TV playing in the background, and then serves you relevant adverts, was "that's cool, but dangerous".

The idea appeared in Technology Review citing Peter Norvig, director of research at Google, who says these ideas will show up eventually in real Google products - sooner rather than later.

The idea is to use the existing PC microphone to listen to whatever is heard in the background, be it music, your phone going off or the TV turned down. The PC then identifies it, using fingerprinting, and then shows you relevant content, whether that's adverts or search results, or a chat room on the subject.

And, of course, we wouldn’t put it past Google to store that information away, along with the search terms it keeps that you've used, and the web pages you have visited, to help it create a personalised profile that feeds you just the right kind of adverts/content. And given that it is trying to develop alternative approaches to TV advertising, it could go the extra step and help send "content relevant" advertising to your TV as well.

We suspect that such a world would be rather eerie, with a constant feeling of déjà vu every time anyone watched TV.

Technology Review said Google talked about this software in Europe last June, and that it breaks sound into a five-second snippets to pick out audio from a TV, reducing the snippet to a digital "fingerprint", which it matches on an internet server.

Given the furore caused when AOL released searches on the internet, there might be more than a few civil liberties activists less than happy for Google to put this idea into practice. Also, given that Google provides the software link between its search software and the microphone, it's a small step to making the same link to any webcams attached to the PC.

Pretty soon the security industry is going to find a way to hijack the Google feed and use it for full on espionage.

Google says that its fingerprinting technology makes it impossible for the company (or anyone else) to eavesdrop on other sounds in the room, such as personal conversations, because the conversion to a fingerprint is made on the PC, and a fingerprint can't be reversed, as it's only an identity.

But we should think that "spyware" might take on an extra meaning if someone less scrupulous decided on a similar piece of software.

The Google program converts sound into graphs, weeds out background noise, and reduces the graphs to key features that can then be translated into just four bytes of information, so that the fingerprints for an entire year of television programming would add up to no more than a few gigabytes, the company said.

Meanwhile, in an unconnected announcement this week, Google said it has signed a multi-year agreement with online auction giant eBay, to provide text-based advertising outside the US.

The companies also plan to launch a "click-to-call" advertising function on eBay using Skype and Google Talk.