[jmm]

The timing of the iPhone (its OS and its app store ecosystem) played a significant role in the check-in model, I think, as it encouraged developers to [finally] sidestep the carriers, and also prevented background processing. Though this is kinda irrelevant to Chris' bigger point of pivoting towards a perceived advantage.

(It will be interesting to see how things change with OS4's background processing. I'd guess users will continue to prefer for check-in based over continuous gps logging, though there may be some interesting/appealing applications of continuous logging. Haven't really looked into the specifics yet.)

[kylemathews]

Google Latitude on the Android follows the continuous logging model. It's interesting but for very different reasons than Foursquare. Foursquare's appeal to me is more keeping a record of interesting places I go and sharing that with others. Latitude's appeal is, oh, where are my friends right now.