New models such as radio ad auction site bid4spots.co.uk and online directory and ideas hub Getmemedia.com are starting to build momentum, while exchanges for online inventory such as Yahoo's Right Media, Microsoft's AdECN and Adjug all now have well- established UK operations.
But two other initiatives, with loftier ambitions, promise to fundamentally change how media is bought and sold.
MediaEquals, an online trading platform that will eventually handle all types of media, has received some impressive backing, albeit for an initial trial period. Bauer and Telegraph Media Group have signed up to the trial, adding to BBC Magazines, CBS Outdoor and agency backing from Aegis, Initiative and Starcom.
Meanwhile, BuyNowMedia, similarly an online trading platform but primarily based on auction technology, is aiming for a full launch in September. The service has the tagline "the online place for media space" and will set out to run auctions for inventory across outdoor, ambient, newspapers, magazines, online, TV, radio and out-of-home.
While refusing to give MediaEquals full backing until a trial period ends, Matt Teeman, ad sales director for BBC Magazines, is enthusiastic about the development. Teeman is pondering which BBC magazines to include in the MediaEquals trial, but he confirms that bespoke inventory will be available as well as standard ads.
"Our inventory will include lots of different formats - there won't be any cut-price deals and it's not about selling distressed inventory," he says. "This is about making inventory more accessible and saving time."
On the agency side, Dominic Williams, Carat press director, has led Aegis' talks with MediaEquals resulting in Carat and Vizeum signing up to the trial. Initially, the two agencies will concentrate on print ads. MediaEquals has so far gained relative success in the press area by signing up Bauer Consumer Media, BBC Magazines, Telegraph Media Group and holding talks with News International, among others.
"There have been people around before talking about this sort of thing," says Williams. "But we've never really taken anyone seriously. These guys seem professional and have the right experience."
But some media agency executives, unwilling to put their name to comments knocking online media trading in case it gathers momentum, say that while media owners gain from new avenues to sell late inventory, media agencies have little or no reason to sign up.
Unease at media agencies is understandable when US operator, Spot Buy Spot, boasts of changing practices to a "factory-like" system, reducing the need for a large office dealing with trading tasks.
To look at the US is to see trading at a more advanced stage than the UK. Google has introduced radio, newspaper and magazine ads to Adwords, its contextual ad system.
Meanwhile, eBay has developed the industry-endorsed Media Marketplace. One significant development is that eBay has partnered with Bid4spots.com to increase its offering to include radio inventory.
But momentum is gathering in the UK for at least a partial automation of the ad trading process. Paul Mann, BuyNowMedia managing director and former online publisher at Haymarket Media Group, is positive that the time is right.
"The fact that MediaEquals, Google and Signposter.com [a WPP outdoor initiative] are all launching, shows that major companies feel ad trading is going this way," he says. "It's never going to be the case that everything is automated and face-to-face will disappear, but this opens up inventory to a wider audience."
There are other developments too. The battle for dominance in the digital sector will result in DDS, MediaTel, IMD, DoubleClick and others attempting to achieve market dominance for their online trading systems. While these battles will likely be played out this year, the next five years will see "more developments in advertising than in the past 50 years", according to a 2007 IBM survey into online avertising.
Half of US ad professionals polled in the survey: "The end of advertising as we know it", said 30% of ad space will be traded online in the next five years - an encouraging statistic for the likes of MediaEquals.
But the report also highlights another major hurdle to be overcome: that almost 50% of ad executives remain unconvinced by ad trading platforms - this in a market that is more advanced in trading than the UK. The early signs are, however, that the UK media industry is, in general, willing to give new trading platforms a chance