John,

Great article, I was wondering where this was going when we discussed it via email :-) I love the idea of location sanity checks as 4 square and google use. If course there are multiple privacy issues are they build a baseline of your travels but maybe thats fodder for another article. It will be interesting to see this trend grow in the enterprise as the BYOD trend continues. It is data thats available and should be used for network security.