I suspect we're going to get bombarded with statistics in the next year, along the lines of "Operator X deployed Vendor Y's offload solution, removing Y Terabytes of mobile data traffic from the macro network and saving $ABCm".
It's also struck me that there's going to be a world of pain in actually validating these claims.
On one side, there is the likelihood that the volumes will be over-stated, because they generate incremental, rather than just substitutional traffic. Generally the offload (WiFi or femto) will be faster and cheaper than the macro network, and so it might reasonably be expected that user behaviour will mean that it sees traffic that otherwise *would not have occurred at all* on the macro infrastructure.
I can quite believe that for every 100MB offloaded, an extra 200MB of "new" traffic might be generated. There probably needs to be a "control group" of non-offloaded users (with similar devices, original traffic and a similar extra software step) for the statistics to be interpreted properly. Before/after comparisons would also help, if adjusted for any underlying growth in data consumption.
On the other side, some WiFi offload will be under-reported, or at least difficult to distinguish from "normal" usage. For example, I've now managed to work out how to do the Vodafone offload to BT Openzone hotspots from my iPhone. But I'm currently sitting a Starbucks, where I can also use the free Starbucks-branded BTOpenzone splash page. Or the BT Openzone hotspot access included with my ADSL broadband package. Or the BT Openzone hotspot access included with my sign-up to FON, the WiFi sharing network.
Now, presumably BT knows which "entry point" to Openzone I use for a given session. But to me, they're all interchangeable, and I'll use whichever has the fewest clicks, or does auto-logon. Which is classified as offload from Vodafone's point of view? And is that a meaningful number given my other options for doing exactly the same thing?
I've been advising some consulting clients about other issues around offload recently. If you'd like to get more detail on Disruptive Analysis' work in this field, please contact me via information AT disruptive-analysis DOT com.
You may also be interested in my recent research paper on Mobile Broadband Traffic Management technologies, from $350. Details available here