So here's the question - what's the saturation rate required for WiFi hotspots before you'd feel comfortable not having an active SIM in your phone? As in, would the knowledge that 80% of the places you usually go have internet access - for messaging, and VoIP, and other uses - put you at ease for not having an active cellphone plan?

How about 60%, or would it take more, like 80% or 90%? How often do you not have data coverage with your current carrier; how often are you in a dead spot where you can't make calls?

There's a tipping point somewhere, when Google can say "look, we can offer you WiFi coverage in XX% of the locations you're normally in" (Google Now is already counting your steps; why not track potential hotspot access too?) and sufficient people will think "yeah, hang on, why am I paying AT&T/etc. $xxx a month?" and the risk of being outside of WiFi coverage is seen as worth taking in return for the savings.

Update: Sources close to the story now tell me that Google hasn't, in fact, acquired ICOA. This all seems more than a little mysterious. 

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Google splashes out $400m on a WiFi hotspot specialist - is this another sign of Google trying to bypass carriers with ubiquitous WiFi connectivity?
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