So what is mobile advertising, anyway? What does it look like? It might seem an odd question, but it’s one that bears investigation.

If you look at the way advertising works in most media, it’s pretty similar and can be summed up in one adjective – interruptive.

Whether it’s the full page ad in the newspaper opposite the gossip column, the banner ad on the Web site where you go to check your e-mail, the 48-sheet poster that stops you in your tracks as you walk down the street, or the interminable ads that break up ITV’s live coverage of any football match in the UK – the process is the same.

We as consumers tolerate advertising, partly because we have become used to it and partly because there is an unconscious acceptance of the fact that advertising makes free – or less expensive –something we might otherwise have had to pay.

Now consider mobile advertising. The rules, to date, have been pretty much the same.

Visit a mobile Web site from a newspaper publisher and you will likely encounter a banner ad at the top of the page. If you’re lucky, there may be a degree of targeting behind the ads, so that a male browser with an interest in golf might see an ad for a golfing weekend break, while a female browser with an interest in ballet might see an ad for a ballet performance. 

That’s the theory, at least.

The same rules apply within mobile apps, the vast majority of which are offered for free. The quid pro quo is that you have to tolerate advertising within the app, usually for another app that the developer would like you to download.

So how comfortably does this interruptive model sit with the typical mobile user, given that the mobile phone is a much more personal device than a laptop or a TV or even a newspaper?

Until recently, the consensus had been that the old model works just fine on mobile. Mobile users see ads on mobile sites and within mobile apps, and they either click on them or they don’t.

Others, though, believe the interruptive model does not sit well with mobile. Moreover, they point to the fact that a large number of clicks on mobile ads are at best accidental, at worst fraudulent.

In a study carried out last year, Trademob, which specialises in driving mobile app downloads, found that 40% of mobile ad clicks were either accidental or fraudulent.

For what it’s worth, I’ve long thought that an ad on a mobile device needs to satisfy one of two criteria: It either needs to be useful or entertaining.

Now, you could argue that if the targeting is good enough, the utility box will be ticked.

Let’s say, for example, that I’ve just emerged from an Underground station and I fire up a mapping app to help me get to where I’m going. If, at this point, I see a banner ad for my favourite sports equipment store, which is just around the corner from where I am now, offering 25% off anything I buy there today, you could argue that ad is very useful.

Alternatively, if I click on a banner ad for a new movie release and am then presented with a 60-second trailer, then you could argue the entertainment box has been ticked.

The trouble is, lots of mobile advertising doesn’t do enough to tick either of these boxes. And, for this reason, there are many who argue it needs reinventing and are coming up with some interesting business models to support their case.

Qriously is one of this new wave of mobile advertising offerings.

Probably the easiest way to describe it is as a mash-up of mobile advertising and market research. So if you’re trying to promote hybrid cars, rather than simply running banner ads promoting hybrid cars, you could use Qriously’s platform to run a poll asking what type of car you are planning to buy next, then serving the ad only to those hand-raisers who select “hybrid” as the answer.

Another start-up, LoopMe, serves ads into an ad “inbox.” Users click on the LoopMe button when they see it on a mobile site or within an app and are then taken to a page of ads or offers. In effect, it’s an ad landing page, so if the user has clicked on the LoopMe button by mistake, they can simply hit the back button to get back to where they were.

The company has already attracted funding and some big-name advertisers, including Marks & Spencer, Honda, and BBC Worldwide.

Another firm, Azullo, has developed a mobile advertising solution called Respond. Instead of banners, it uses simple text links within editorial content.

The ads are targeted, using the editorial content as the targeting parameter. Inventory can be bought on a CPC (cost-per-click) or cost-per-engagement basis, in which the advertiser is only billed when the content has been viewed for a minimum of three seconds. This is designed to prevent advertisers from having to pay for accidental clicks – a useful safeguard when you consider that Respond ads don’t look much like ads and could be mistaken for part of the editorial content.

A number of UK publishers use the Respond platform, including IPC, Dennis, Future, and the Manchester Evening News.

Who knows which of these new advertising offerings will stay the course. But it’s interesting that there are so many of them; I’ve offered just a small selection here. It’s proof, perhaps, that thinking of mobile as online on a smaller screen is probably the biggest mistake you can make.