Here's an unformed thought: mobile billing has always been about aggregating small charges: a text message here, a voice call there. Implicit in this is the idea that tiny changes in consumer behaviour, expressed over a large population, can make a big difference to those profiting from these changes.

For example, imagine you're a hypothetical UK operator with 15 million customers, and you get them, on average, sending a single 30 pence MMS message each month. That level of traffic is pretty minimal, and I'm sure wouldn't help analysts perceive MMS as having been "successful" (as if there is any such binary test for success with these things!). But it would bring in £3.60 p.a. per customer, which translates to £54m annually purely in message charges.

I also suspect there would be knock-on effects - that receiving an MMS typically stimulates a response as a text message, or as a call. Or that owning an MMS-capable phone makes you more likely to use other chargeable services, like gaming or an online portal.

Even without these extras, it's significant extra revenue from a small change in behaviour. I'm not suggesting that bringing about such changes is easy, of course. But many new services seem to target a small subset of overall mobile users, and ask them to pay significant sums - a pound per month, 5 pounds per month. As operators demonstrate every day, this isn't the only approach that works.