This summer has seen no let up in the use of celebrities to flog products ­ be they magazines, TV programmes or sports gear. Still, with Euro 2008 in full flow, would we expect any different?

One brand owner which adopted a slightly different take on the subject, however, is that wily media owner BSkyB. From mid-May onwards viewers of all digital terrestrial TV networks have been treated to the sight of the likes of Sir Michael Parkinson, Felicity Kendal, Mariella Frostrup, David Gower and Ross Kemp talking up the benefits of Sky .

For the uninitiated, Sky claims to be the most successful digital tape recorder in the UK, enabling 12 million people every day to record, pause and instantly rewind live TV.

So, what makes this campaign's use of celebrities any different to, say, Kate Moss's ads for Rimmel? Well, Sky has gone a step beyond straight endorsement, and moved into the area of advocacy. The celebs that it is using are all longstanding Sky customers, who are talking unscripted about what it's brought to their lives. In some ways, it represents a gamble for Sky. Will customers believe what they say?

Lucian Smithers, BSkyB head of brand marketing, talks about the original brief as trying to get under the skin of the product and communicate what people feel about it. "We sit in consumer groups and talk to customers a lot," he says. 'We've also spent a lot of time, money and effort telling people what Sky does, but we've never really managed to make the leap between what it does and what people feel about it."

Its new campaign had to take what many potential viewers could see as a very technical topic, put a human face to it, and convey the simplicity of what is ­ at its best ­ an intuitive device. And one which would make them look at television in a new light.

The company has used a number of measures to assess effectiveness: advertising tracking, contact and sales data, plus qualitative pre-testing. The latter enabled Sky, by virtue of the different edits, to select and shape how the messages are sequenced: moving from celebratory language, to simplicity of use, functionality and so on.

It did, says Smithers, have to overcome cynicism in qualitative groups. Hardly surprising in an era when companies in countries like the US are starting to be slightly wary about using famous names in promotions. What made the difference in those groups, he adds, was that respondents felt the personalities used were speaking from the heart ­ so the footage distanced itself from the problems experienced in the US.

So will we see a move towards advocacy rather than straight endorsement? Well, Sky is banking on there being sufficient mileage in the promotion to introduce a younger element in July, Kelly Brook, to broaden its appeal. The proof will lie in sales figures of Sky in coming months.