What everyone forgets about services such as mobile, broadband and even TV is that they are largely customer care logistics businesses. This is why Centrica has toyed with everything from the AA to broadband provision.
Of course, with content now dispersed over TV, broadband and mobile there is further coherence to the quad play. Some years ago on this blog I predicted that the mobile phone would become both a remote control and wallet. This has now happened and it is the one device you therefore need to have control over when running an integrated media infrastructure service.
Sky is a very sharp business and it will be interesting to see how they use their content portfolio to leverage this new venture. However they are more and more dependent on others' infrastructure and network and this is a potential weakness.