This has been under the radar. Two companies in Sir Martin Sorrell’s WPP Group are working together on a paid content initiative (don’t call it a paywall), called The Content Project (TCP).

It hopes to create a network of publishers who will offer readers an electronic wallet for buying content across a range of sites.

It is slated to launch in the first quarter of 2011, which is about the same time The New York Times plans to erect its metered paywall.

The idea behind the Content Project is that users pay a fixed fee each month, giving them an electronic wallet, to access a pool of content. The fee is then shared out between the media owners rather than paying one fee to a single company.

TCP describes the system as a “flexible platform [that] enables publishers to offer premium, paid content while increasing the value of their advertising inventory. Through TCP, WPP provides online content providers with a unique value proposition, a one-stop revenue solution that combines advertising with consumer payments.”

It sounds a little like Steve Brill’s Journalism Online project, which Rupert Murdoch’s News Corporation took a stake in recently. Similarly TCP will take a slice of any revenue generated. It also echoes the rumoured Google paid content venture reported earlier this year, but with little heard of since.

TCP is a joint venture between WPP digital subsidiaries 24/7 RealMedia and Schematic and has been in development since the start of this year. It is being headed by general manager David Restrepo the former client services/strategy director at Schematic and prior to that the founder & CEO at CarePilot.com.

What’s interesting about this project is that news of it has emerged only weeks after Sorrell stressed that paywalls were “essential” for publishers in the digital age. Sorrell told Brand Republic that as far as WPP is concerned giving away content for free makes no sense. “Consumers have to pay for content they value,” Sorrell said.

Restrepo told Fast Company that the ambition of TCP was to create a network of publishers agreeing to a common platform that can then be rolled on a broader scale.

“From a consumer perspective, you won’t need dozens of accounts at different places. Is it unique? No, it’s been talked about it, and there’s been tons written and theorized about paid content,” Restrepo said. “There are case-by-case examples for paid content–WSJ, Hulu, ESPN.com–but we’re of the opinion that we have to experiment much more.”

That the project has not been announced with any WPP fanfare suggesting that it is almost under the radar. A side project being given some space to develop. Restrepo adds weight to this idea when he tells Fast Company that TCP will need to “experiment before it can draw any hard conclusions”.

Should it progress, what is clear is that WPP has excellent relationships with publishers on a global scale. That could prove important if TCP does put together its initial network and, as Restrepo says, add some scale.

But whatever you do don’t call the Content Project a paywall. Restrepo doesn’t like the term.

“Don’t think of The Content Project as another quote-unquote paywall solution,” Restrepo told The Atlantic, “We do not like the term ‘paywall’ or even the idea or metaphor. It’s sort of an all or nothing.”