I don't know ZYB at all, never used it. Worked 6+ years ago at Vodafone so here's my quick response: Vodafone is basically a bit pipe, not a content provider. Wireless is a commodity so they try to improve their margins and move towards content.
They did similar acquisitions in 2002 (someone remember Vizzavi) for the same reasons. The only difference now that mobile technology improved (3G network, handsets, etc) and that content might bring in some bucks unless they don't charge extreme (data or subscribing) rates.
In general I think it is a bad buy; any other popular ZYB variant could start their own mobile spin off.
Arun Sarin should keep focussed on the integration of the several OpCo's (who only got a label Vodafone stuck on them but are in general just seperate companies).