How Wi-Fi saved 3G from the iPhone

...the answer is simple enough: traffic offload...
...In other words, Wi-Fi hot spots in cafe and food courts could be transformed into the equivalent of public femtocells...
...PCCW in Hong Kong already has a 3G/Wi-Fi offering for its Netvigator service via a dongle that recommends the best connection (although it doesn't support handoff at the moment).
Interestingly, another element driving 3G operator interest in interacting with Wi-Fi is the iPhone.
In May, for example, SlingBox released an iPhone version of its controversial SlingPlayer app, which allows you to tune into your SlingBox-enabled pay-TV set-top box at home and watch cable TV on a PC or, in this case, an iPhone. AT&T - via Apple - only greenlighted SlingPlayer for its iPhone customers after SlingBox agreed to configure the app to work only through the iPhone's Wi-Fi link, not over AT&T's HSPA network.
Reason: "Slingbox, which would use large amounts of wireless network capacity, could create congestion and potentially prevent other customers from using the network," AT&T said, adding that there were over 20,000 free Wi-Fi hotspots in the US iPhone users could access to sling their video.
A month earlier, AT&T took a similar and more controversial approach to iPhone versions of VoIP apps like Skype and TruPhone. Both apps only work on Wi-Fi links. This time, AT&T was even more candid: "We have no obligation - nor should we have - to facilitate or subsidize our competitors' businesses."
And there you have it: 3G operators that once worried about Wi-Fi cannibalizing their business are now relying on Wi-Fi to keep web-based apps from eating into their business - and their network capacity.
See what they did there?

source: telecomasia.net