O2 has announced the launch of a new network of (initially) 450 "premium managed" WiFi hotspots available to be used by customers of any mobile network. Access will be free although customers will have to sit through some adverts. It plans to make it the biggest WiFi hotspot network in the UK. To do so it'll need to outstrip The Cloud's 22,000 hotspots and, arguably BT FON's 2 million, although they might argue reasonably that that's a different thing entirely.
This follows on from the all-very-meteorological announcement that Sky is in to buy The Cloud, which had previously been O2's partner for WiFi connectivity. If Sky is to make a serious play as an MBB MVNO it needs some differentiator (and some way to avoid paying wholesale fees for all the traffic consumed) so picking up The Cloud's extensive network of hotpots seems a good move.
So, as predicted by me last year, offloading is the only game in town and mobile players are jockeying to have a service differentiator (in the form of superior throughput in areas of high demand) and cost reduction tool (WiFi's "cheaper" than WAN connectivity because the spectrum's free).
The cloud (pardon the pun) on the horizon is that the unlicensed spectrum in which WiFi works could soon be clogged up. Just because it hasn't happened yet doesn't mean it won't. It's a finite resource and it's shared with all sorts of other technologies (DECT, Zigbee, Bluetooth) and other ISM applications including microwave ovens and car alarms. Offloading to WiFi is all very well in the home where there's are only ever likely to be a handful of users sharing the spectrum. In key public pinch-points like railway stations or airports there could be problems. Issues of lack of licensed spectrum can be overcome by the operator through frequency re-use. Drop the power and put in another transmitter or two. With public spectrum there is no incentive to act so responsibly.