A quarter of a million customers have signed up for O2's i-mode service in the first six months since its launch, three-quarters of whom are now regular users, O2 announced on Tuesday.
This rate of adoption made O2's i-mode the fastest-growing version of the service outside of Japan, said Grahame Riddell, the company's head of content marketing.
At a briefing on O2's progress since it launched its i-mode service in September 2005, Riddell claimed that uptake would have been even greater had O2 not had problems with the availability of its first five i-mode handsets.
He said that i-mode had been successful in "getting people to use the types of services that have been successful on the Internet".
Citing the heavily promoted i-mode eBay portal as an example, he said that the time UK users had typically been spending on i-mode was equivalent to 60 percent of the time they spent on the standard version of the site.
Analyst Dean Bubley of Disruptive Analysis believes there is a "gap in the market" for optimised mobile versions of such sites.
However, he told ZDNet UK that ultimately, services such as i-mode will be redundant. "Over time, browsers will get better, and browser-based access to those services will become more prevalent," he said.
Last month, the first .mobi domains — for Web pages optimised for viewing on a mobile phone — were launched.
Riddell also unveiled future ideas for the i-mode portal. One will be to attempt the incorporation of an RSS aggregator, called i-channel, into the system, with an RSS ticker running across the handset's idle screen.
Another plan is to bring in an instant messaging (IM) client, which would theoretically be interoperable not only with the IM clients of rival operators, but also with more traditional clients such as MSN and Yahoo.
Jag Minhas, O2's chief i-mode architect, admitted that it would be "really hard for an operator to launch a service that relies on a community from scratch", when faced with the large communities boasted by existing PC-based IM services.
But Minhas added that O2 is "very keen to see that presence is not a prerequisite for conversation", and stressed that its IM client would draw on the device's unified address book rather than separate buddy lists.
In this way, Minhas said, users would even be able to IM someone whose handset was only SMS-capable.
However, Bubley remains sceptical about the mobile operators' claims that their IM clients would be truly interoperable.
"They're trying to link up some walled gardens," Bubley said. "A segment of the market will tolerate that, but others will want to jump the wall.
"Fundamentally, people will get their IM where they do at the moment, from MSN, Yahoo and so on," he said.