Mobile TV viewers in Norway will be served personalised adverts as part of a two-month trial.
Banner adverts will be sent to mobile phones and tailored to the individual user under the trial by broadcaster NRK, a mobile TV pioneer.
"Advertisers see value in people being interested in certain products in a given context," said Gunnar Garfors, director of development at NRK.
Two TV channels and four radio stations are taking part in the trial.
"Most people who watch mobile TV in Norway do so because they are bored somewhere, on transport, or waiting," said Mr Garfors.
"You can assume they are near a shop or service which may be relevant."
The TV and radio stations are streamed to the phones over a 3G phone network and are "near-live with a few seconds' delay.
Mobile TV is a growing market that is yet to hit the mainstream partly because of cost and partly because of competing mobile TV standards.
Unlike other "live TV services" on the market, the NRK trial is streaming video rather than broadcasting it.
According to research firm eMarketer there are 44.5 million 3G subscribers worldwide who watch mobile TV on their phone. Their report predicts the number will double each year, reaching 520.9 million by 2009.
The number of subscribers who pay for premium video services and watch them on their phone will go from six million worldwide to 121.5 million by 2009, it predicts.
Adverts from 20 different companies are targeted to the viewers, depending on the information given to NRK when they signed up for the trial.
Mr Garfors said: "We know lots about the viewers; we have their phone numbers, their name, sex and where they live.
"We can also determine their presumed interests when we see what they watch or listen to and what times they do it.
And we know where they are geographically because of positioning technology.
"When we put this all together we have a fair amount of relevant information which can give them more relevant advertising material."
While the trial is a "proof of concept", Mr Garfors said future developments could see adverts sent to phones dependent on the precise location of the viewer.
For example, companies could have adverts sent to viewers matching their target demographic who happen to be waiting for a bus close to shops where their products are on sale.
People taking part in the trial download a small computer program - a Java application - onto their phones.
The application is also used to change channels on the phone as well as to give viewers the chance to vote interactively during programmes, and send audio and video messages.
"You can also watch or listen to on demand programmes."
Norway is pioneering mobile TV and radio, said Mr Garfors.
"It's beyond the early adopters. Most phones are 3G and they all have built in video players. It's quite popular."
Cost continues to be a barrier for many people, however, as mobile operators charge customers for the data - in this case video or audio - that is downloaded on to their phones.
Mr Garfors said: "One of the problems is that the operators have different price systems. It's still assumed to be quite expensive."
But the introduction of flat rate subscription services - for about ?3 a month - could open the floodgates to more viewers.
Mr Garfors said NRK was pioneering mobile TV because of changing viewing habits among the younger generation.
He said: "We are losing out on younger viewers and listeners when it comes to traditional TV and radio.
"On the mobile platform they are big users. If we are just going to continue to do traditional TV and radio, who knows who long we will be in business?"