In a service economy, there are thousands of similar small businesses, including many self-employed independent traders, for whom the internet must seem an irrelevance: skip hire, waste removal, pest control, television aerial installation. child-minding, dressmaking. Just open Yellow Pages and have a flick through.

Such businesses, mostly local, usually attract new customers through a combination of personal recommendation and traditional advertising — particularly in Yellow Pages and other similar directories. Until now, they have had no use for the web.

But the internet is extending its reach ever further into the offline economy. Espotting, a British company that is part of FindWhat.com — an American rival to Google and Yahoo — is working on the launch of a new form of internet advertising that will make it relevant for tens of thousands of offline businesses.

Pay-per-call is a further development of “paid search” — the business that has generated hundreds of millions in revenue, and billions of dollars of stock market value, for Google and Yahoo. With paid search, advertisers bid for the search terms — car insurance, or holidays in Cornwall, say — that will attract traffic to their website. They pay only for each potential customer who clicks through to their site — making the cost of generating sales easily measurable.

With pay-per-call, FindWhat and Espotting will create their own searchable directories, listing the telephone numbers of plumbers, electricians and any other advertisers. But the advertisers will only pay when customers call through to them.

Seb Bishop, chief marketing officer of FindWhat, claimed the new service would remove the need for small businesses to display any degree of internet-savvy. “They will sign up to a process, and they will start to receive phone calls,” he said.

“The early adopters will be those who have had great success with pay-per-click. But it opens it up to millions of businesses that were never able to tap into that because they never had a website.”

Pay-per-call, like other forms of paid search, tackles one of the oldest problems of advertising. As Lord Leverhulme fam-ously put it: “Half the money I spend on advertising is wasted. The problem is, I don’t know which half.” With paid search, advertisers can tell exactly what works and what doesn’t.

FindWhat launched pay-per-call advertising in America last autumn, and plans to introduce it in Britain later this year.

Faced with this challenge, it is little wonder that Yell, the company that owns Yellow Pages, is building up Yell.com, a small but fast-growing part of its business. Yell.com last week linked up with Google to provide 2m business listings to a new Google Local service.

These developments are only one example of the way the internet is continuing to have a far-reaching and often unexpected impact on business.

Ten years into the internet age, most office-based workers have ceased to wonder at the ease of access it gives to voluminous amounts of information on every topic under the sun. But after the bursting of the first internet bubble five years ago, and the collapse of so many of those quirkily named companies, much of business seemed to return to normal.

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