Advertising on mobile phones has enormous potential to become a significant platform for marketers, but any breakthrough is years away and major operators must work together to succeed, executives said.
Mobile operators increasingly see advertising as a powerful offering, given falling traditional voice revenue, as it allows brands to target consumers based on their location and at times of the day when they are otherwise hard to reach.
Executives from advertising and telecoms groups told the Reuters Technology, Media and Telecoms summit mobile advertising was inevitable and would become hard to resist.
But it was still at the experimental stage, and many brands and mobile operators were wary of alienating customers.
"It will be slow, it will take time but it will be there," Maurice Levy, chairman and chief executive of advertising group Publicis, told the summit in Paris.
"Why? Because it will be in the interest of the phone companies, consumers and advertisers. So it will be very difficult to resist."
Forecasts suggest the mobile ad market will generate revenue of $1 billion to $24 billion within the next 4 years.
Many operators are experimenting with plans and one service, Blyk, has signed 100,000 clients in the UK with its offer of some free calls and text messages in return for accepting ads. Reuters' Kate Holton and Niclas Mika report