Colleen Caldwell loves to share. Via her blog, Simplekindoflife.com, readers have learnt that she thinks Bruce Springsteen is hot and that she has had a saucy dream involving Rainn Wilson, an actor in the American version of The Office. Whenever there’s a new movie, TV show or confectionery product that Caldwell feels psyched about, her audience are the first to know. Take The Ultimate Gift. “Has anyone out there read a book called The Ultimate Gift?” she frothed recently. “I heard a movie is being made of the book, which sold 4m copies.” The software analyst from Florida later praised the film’s inspirational message, suggesting that everyone should take advantage of a promotional discount at the box office. What she didn’t mention was that the producers were paying her £6 every time she namechecked their film; her blogging-for-money total is now more than £3,800.

Caldwell and hundreds like her are cashing in thanks to PayPerPost, a company that crosses the line between advertising and personal recommendation, hooking up marketing departments with grassroots webcasters. Caldwell has blogged about everything from wireless outdoor speakers to her local French restaurant. You can, too. PayPerPost is looking for anyone feeling suitably inspired to rave to their friends about the reformed band the Police (£10 a shot), the American hardware shop Ultimate Paintball (£10) and the online business Hotelreservations.com (£3).

“This is a new way of looking at advertising,” says Tim Draper, a PayPerPost stakeholder. “You put an ad inside the text, and it’s more subtle.”

Others disagree. “If you’re going to advertise to me, tell me you’re going to advertise to me,” says Mark Waites, a partner at the London ad agency Mother. He disapproves of such strategies as record-company employees posing as teenagers on MySpace. “These people use phrases such as ‘stealth advertising’ and ‘coming in under the radar’. But it’s actually lying. There’s panic in the music industry, and people will try anything. Kids are hanging out in chatrooms, so they infiltrate that space. It’s really low.”

Such underhand schemes suggest that the ad industry is struggling to reach consumers, who have become immune to more conventional approaches. Twenty years ago, advertisers could reach the majority of the UK population by taking out just three TV adverts. These days, we watch hundreds of different channels. The YouTube generation would be horrified at the notion that you have to consume what you’re given: they mix and match what they want, when they want.

Hence sneaky new ways of trying to get the message across. Last year, Saatchi & Saatchi launched the ultimate manufactured band: a then-unnamed girl group it had put together with the help of a panel of music-industry experts, for sale to whichever company wanted to rebrand them. The aim was to infiltrate young R&B fans turned off by traditional advertising. In the end, it was Radio 1 that did the turning off: Honeyshot, as they were eventually christened, were banished from the playlist after they were rumbled as being on the payroll of Shockwaves, the hair-products company.

Agencies such as Taxi Promotions UK use civilians to spread the word: in their case, by taking cabbies on free holidays to Las Vegas and Thailand in the hope that they will witter on about it to their captive audience of passengers.

“More and more traditional advertising is either ignored or lacks credibility,” says the communications strategist Tom Himpe. “Brands now realise that they need to enter people’s environments to get closer to them.” Himpe is the author of Advertising Is Dead, Long Live Advertising!, a coffee-table book full of examples of this “buzz marketing”: the blonde model in the Hard Rock Hotel dressing gown who wanders around a park in Chicago, asking commuting businessmen if they know the way back to the Hard Rock Hotel; the bloodied luggage hanging out of public lockers to promote CSI: Crime Scene Investigation; the antismoking campaign that stuck flags into dog mess on the streets (“Cigarettes contain ammonia. So does dog poop”).

Regardless of what the Advertising Standards Authority might have to say about such schemes, do they actually work? “It’s very risky,” Himpe says. “Consumers do not like to smell the sell. Brands need to adhere to a few basic rules and be open and transparent.” He says that Innocent, the smoothie company, is a good example of a company that understands this. “Even when it did a deal with McDonald’s, the company put it on its blog, explained why it was a good thing for it, and asked people honestly what they thought. It created a vibrant, beneficial conversation within their community.”

For the marketers who feel their message still isn’t getting through, there is another option: give the stuff away free. The brewer Scottish & Newcastle has just mobilised a 250-strong team to visit 6,000 pubs, chat to customers about their boozing habits and then buy them a drink. Thousands of pints of Foster’s, Kronenbourg 1664 and Strongbow will be handed out between now and the end of August. A couple of months ago, Carbon Marketing deliberately jackknifed a lorry in Covent Garden, in London, spilling boxes and boxes of chocolate bars made by its client Nestlé onto the pavement. Apparently, 70,000 passers-by “sampled” the consignment, only too pleased to fill their pockets. Blyk, a start-up mobile-phone company run by Nokia’s former president, is offering teenagers free text messages in return for being regularly interrupted by adverts (Coca-Cola, L’Oréal and Disney have so far signed up to the scheme).

The forecasting agency Trendwatching.com has coined a term for this sort of thing: “tryvertising”. It cites the examples of Tadacopy, a Japanese firm that offers students free photocopies on A4 preprinted with adverts, and Gratis-Post, the Dutch service from which customers can order envelopes with free postage on the front... and adverts on the back. “Consumers don’t mind getting their hands on free stuff, so long as the ads are not too annoying. There are plenty of opportunities for this,” says Reinier Evers, the founder of Trendwatching.com.

If all this leaves you despairing that the advertising industry is getting a bit, well, desperate, perhaps it has always been the case. “Several years ago, a well-known trainer company went into working-class areas in America and doled out free shoes to a handful of ‘opinion-former’ kids aged between 14 and 18,” says Mark Ratcliff of the research consultancy Murmur. “Then they sat back and waited for demand to flare up. They told me where they appropriated that idea from,” he continues. “Crack dealers.”

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