If banner isn't the answer, then, er, um, what was the question again? Even during the periods when it was an unquestioned assumption that the internet had a huge future as an advertising medium, there has always been an underlying sense of disquiet about the models on which that optimism has been based. Could we really have everything riding on banner ads? Those little strips that would be laughably easy to ignore if they didn't offer the technical magic of a click-through to another site.
A couple of years ago, even before market hype really got going, a number of major advertisers in the US set up an industry group to look into the future of online advertising. Their conclusion at the time was that banner was boring, but other formats such as interstitials and superstitials were too intrusive. Unfortunately, they failed to conjure up a third way.
And you can't argue against market growth - over the past two years, the banner has been delivering.
But not anymore. Year-on-year revenue growth, according to many estimates, will be negligible this year. According to other predictions, especially US ones, the situation could be a lot worse than that. And at a time when there is widespread anxiety about even bigger questions - such as the whole future direction of e-commerce - it's no surprise to see advertising formats coming under even greater scrutiny.
Click-through response rates keep falling and are now well below 1 per cent, which somewhat undermines the return on investment model that was once promoted enthusiastically by the online community.
Many will point to the fact that some of online advertising's biggest supporters - the big dotcoms - are no longer with us. In other words, the slowdown is not a measure of the medium's effectiveness. And the great hope is that mainstream advertisers will move into the medium in force, replacing dotcom money. But that takes us back to square one: brand advertisers find banners unappealing.
Surely, what we need is a reappraisal of the medium? Well, help may be at hand. Last week, the Ad Unit Task Force of the Internet Advertising Bureau (IAB) announced revised voluntary guidelines covering online advertising formats. What they are recommending is the introduction of bigger, squarer formats. Formats such as mini TV screens that can sit in the middle of web pages.
A welcome development? Neil Perkin, the digital ad director of IPC Media, believes these new standards offer greater opportunities for advertisers to make creative treatments work harder. He welcomes this, obviously, but points out that it is no revolution.
Perkin says: 'We've been running a non-industry standard vertical banner on BeMe.com for over a year and achieved average click rates four times the industry average. The real issue is less what shape ad a client is running and more what you put in it, how accountable it is, and how brands can be integrated to broaden campaigns beyond the banner.'
Others agree that this is a very small earthquake. David Bryant, the creative director of Tribal DDB, believes: 'The medium is as good as the creative work that runs in it, and, frankly, setting the template sizes is a bit of a lost cause.
If you want to do something creative you go to the media owners direct.
The IAB's heart is in the right place, and its role is to stimulate meaningful dialogue, but rather than recommending other formats it should perhaps be encouraging a greater degree of flexibility within existing formats.'
Some would go even further to say the whole initiative smacks of media owner desperation.
James Booth, the director of the internet advertising technology company Tangozebra, would not go quite that far, but he does agree it is a reflection of how much harder it is for sites to find revenue.
'They're wrong if they think they can slam something in the middle of content as a quick fix,' Booth argues. 'It ignores what technology has to offer. You can't just say, 'banner isn't working so let's make it bigger'.
It will come down to the end-user. If you start putting huge things in the middle of content then people will just move away and the value of the real estate will merely diminish further. From where I'm sitting, we have technologies that allow ads to be delivered without cluttering up the homepage. Our techniques make them feel more part and parcel of the content of a site. I think subtlety in advertising is important and the way to do it is to find technological solutions.'
Fair enough. But many brand advertisers looking to enter the medium naturally want to re-purpose what they already have in the way of creative work and the problem in the interim is that rich-media advertising isn't a viable option as yet. Many sites can't handle it. In other cases, the cost of video streaming is prohibitively expensive.
In other words, one way or another, we're stuck with banner for a long while to come. Booth concludes: 'We're going for effectiveness of interactivity that is very viral - for instance, games you can send to a friend. Banners still have a role in that. And there are still lots of people who believe there is life left in banner. The thing is, I think you have to use it not as a 10k animated Gif but as a letterbox through which you can find a whole world.'