When Tesco TV debuted in 2004, it was regarded as a revolution that could threaten TV in the home for its share of advertising.
But what started with a bang tailed off amid reports that the new medium was not as successful as had been hoped and it became clear that advertisers faced far more of a challenge for shoppers' attention compared to TV at home.
But there are unique selling points to in-store TV, which media agencies and supermarkets are now becoming wise to, as witnessed by Sainsbury's decision to extend in-store television from 180 to all 300 of its Local outlets.
Asda and Woolworths have both followed Tesco and Sainsbury's by trialling in-store TV in the last six months, with Asda testing it in stores in York and Wembley, London. Retail chain Spar signed a £9m deal with Avanti Screenmedia in September, with chief executive David Williams citing the smaller convenience stores as better fitting the medium than large supermarkets.
David Treadway, managing director of Firebrand, which provides Sainsbury's with its in-store TV, says its flexibility is its advantage.
"We focused on convenience stores because of their unique characteristics," he says. "The majority of people who use convenience stores use them on multiple occasions per week. In a big store, by and large people make less visits."
Treadway explains that convenience shopping is all about distress and top-up, and that the challenge is to make shoppers' baskets bigger. "We can remind them of something they might have forgotten and target them while they are waiting in the queue.
"If you are watching Coronation Street and an ad for The Sun comes on, you can't do anything about it, though you might remember it and act on it the following day. If you are at the point of purchase you can do something immediately."
Given that the customer may well return the following day, it works on the basis of referral and creating brand awareness, as well as seeking the impulse reaction.
Treadway claims this approach is working. The average uplift of sales for advertisers who have used Sainsbury's Local in-store TV is 26%, with one bread brand in particular experiencing a rise in sales of 125%. Other bread brands also reported increases during that campaign.
In Firebrand's in-store advertising for The Sun in Sainsbury's Local, what's on screen can be adapted to advertise the stories that are in the paper that day. Firebrand is planning advertising for a petrol brand with ads that will alter according to the weather, with windscreen wipers advertised when it's raining, for example.
The medium has certainly had to move away from the one-size-fits-all of the early days towards a more targeted approach.
This is just as well, says co-founder of consultancy Retail in Action, Richard Savage.
"I haven't seen anyone get it right yet," he says. "It is an interesting medium and can be used to much greater effect than it is now. Customers are not seeing a fraction of the messages already there at the moment.
"Supermarkets seem to have been putting a lot of screens where there is space, quite frankly, and it has been led by the technology."
Savage doesn't see in-store TV as a replacement for home TV advertising, rather as an opportunity to communicate with quick, occasional messages that are aligned with the needs of the individual shopper.
Media agency OMD UK's managing director, Jonathan Allan, reiterates the need for a more integrated approach in future.
He says: "While recent models and empirical research clearly demonstrate the power of point-of-sale communications, the major grocers should think in a more integrated fashion about how they package and sell their in-store opportunities across all their contact points, not just focus on single media, as this would multiply the results beyond what is achievable just through TV screens."
Tesco, the UK's largest retailer, is also reassessing the way it uses in-store TV in 100 of its stores and has recruited a new agency, Dunnhumby, which took over from outdoor specialist JCDecaux in August. One of the first things it did was to reduce the rate card, perhaps reflecting the disappointment of advertisers in initial returns.
Instead of having screens in the aisles, generally showing ads in much the same form as they are on TV, Martin Haywood from Dunnhumby says the trend now is towards tying in what is on the screen with in-store promotions and other types of advertising in store, such as shelf talkers and above-the-line campaigns.
Like Sainsbury's, screens are being used at the checkouts where its audience is captive. "It's growing up in terms of quality of analysis and making sense of what it's for," says Haywood. "In-store TV is maturing as a medium."
WHO HAS IN-STORE TV?
Sainsbury's: Currently in 180 Sainsbury's Local stores, expanding to all 300 by the end of 2007
Tesco: Currently in 100 stores, being reviewed
Asda: Trial just completed in two stores, one in York and one in Wembley
Woolworths: Trial just completed in 12 stores across the country and results being collated
Spar: Spar TV set to begin in 203 stores, with a view to rolling it out to independent franchises at a later date
Co-op: Currently has digital posters, no plans for in-store TV at present.