Does Foursquare use the very last step in the description? My understanding is they update location when user "checks in", not when system detects that the user's device is stationary.
The NPE's are really just a more updated version of what personal injury lawyers have been doing for years. There is a leg to stand on, and it results in a shake down (in many but not all cases of course I'm not claiming there isn't infringement). So there are valid claims and there are bogus claims. Trying to divine between the two is going to be like filtering spam. Redesigning the system from the ground up is as likely as the same type thing happening with email and how that's currently handled.
Perhaps the next thing, while not as profitable, will be shakedowns with respect to trademarks. I actually had that happen maybe 5 years ago when a large bank (UBS) objected to a trademark filing and extorted a minor concession in order to let us have a trademark on a non-bank related business. Cost a few thousand in legal fees and delayed the trademark from being issued.
I agree, the patent situation is a mess. And this is probably a terrible patent encumbered by all sorts of prior art. But on paper, it's a pretty good leg to stand on.
What matters are the claims.
The first patent, US7475057, looks very very simple: it's a single standalone claim regarding:
* using a GPS receiver
* to populate a database
* by reading the GPS from a personal computing device
* when the device comes to a stable location
* sending that location to the server
* reading data about the location back from the server
* having the personal computing device request that the server save that information in a record associated with a user
* by using a system of detecting that the device has become stationary involving (i) reading the GPS, (ii) waiting, (iii) rereading the GPS, (iv) seeing if the location changed substantially.
This is a single claim; you'd have to be doing all of these things to infringe that patent.
(It's a remarkably broad claim and a dumb patent, although it was filed a fair bit before personal GPS devices were common).