Did anyone else think that email started out sounding like a nigerian money scam?

If you RTFA, the patent was filed in February, 2007. Foursquare wasn't launched until March 2009 according to wiki. So at least in the case of Foursquare, I don't see how they can claim prior art. I'm pretty sure Google Latitude was launched in 2009 as well. I can't speak to other systems though.

> This is one reason you should send user friendly error messages to your consumers instead of stack traces...

Right, and isn't the default CustomerErrors setting in ASP.NET set to RemoteOnly? Meaning that that the exception & stack trace are only sent when you are browsing from localhost? If you were dumb enough to send full errors from a production system, then you deserve to have your application exploited by this.

OnStage free version http://www.onstageportal.com... Although I'm a one man team so my task list needs are not that complex.