The award of top prize at the world’s most important advertising festival to an internet campaign for Unilever, the household goods group, may come to be seen as a milestone for the web’s development into a marketing medium.

The “Evolution” film for Dove, Unilever’s skincare brand, is among the most prominent commercials to benefit from a large element of free distribution on the web after being posted on websites such as YouTube and blogs.

Most internet advertising has hitherto been classified-style listings on search websites, but the “Evolution” clip used film techniques to show a young woman being transformed into a glamorous model.

Its capture of the film Grand Prix at the 54th Cannes Lions International Advertising Festival will re-enforce the mood of qualified optimism expressed by many senior industry figures at the event. They believe mainstream marketers are embracing the branding opportunities offered by digital media as well as recognising the threats such technology poses to traditional working practices in the $400bn-a-year global paid-for advertising sector.

In recent years, several factors have combined to cast doubt on the effectiveness of mainstream marketing approaches.

They include the changing habits of Western consumers – particularly declining readership of paid-for print titles and greater use of the web – and fears that over-exposure to commercial messages had jaded audiences’ interest in advertising.

Simon Rothon, senior vice-president, marketing services global at Unilever, told the FT: “I was here two years ago. There was an incredibly tense feeling, almost as if the industry was losing its confidence.

“But I found a lot of confidence at this year’s Lions about agencies’ ability to play all the keys.”

At the Lions, marketers argued that digital media allowed companies to create a more conversational approach to reaching their consumers, often by provoking debate on current issues.

“Evolution”, which is part of a long-running campaign to present Dove as a brand that questioned stereotypes of female beauty, certainly fits that bill.

It was created by the Toronto office of Ogilvy & Mather, the advertising agency owned by WPP, the UK-listed marketing services group.

Another theme of this year’s Lions was the success of advertising that combined free and paid-for media placement, and mixed digital with conventional television and press elements.

In addition to Ogilvy’s success, the New York office of Saatchi & Saatchi, owned by Publicis, the Paris-based marketing services group, sealed its return to creative favour by being named agency of the year.

BBDO, part of Omnicom of the US, was the network of the year.