[The ACLU has a new] report, Policing Free Speech: Police Surveillance and Obstruction of First Amendment-Protected Activity (.pdf), surveys news accounts and studies of questionable snooping and arrests in 33 states and the District of Columbia over the past decade.
The survey provides an outline of, and links to, dozens of examples of Cold War-era snooping in the modern age.
“Our review of these practices has found that Americans have been put under surveillance or harassed by the police just for deciding to organize, march, protest, espouse unusual viewpoints and engage in normal, innocuous behaviors such as writing notes or taking photographs in public,” Michael German, an ACLU attorney and former Federal Bureau of Investigation agent, said in a statement.
For example, it seems FourSquare had an interesting failure of threat modeling, where they failed to grok the information disclosure aspects of some of their pages. See “White Hat Uses Foursquare Privacy Hole to Capture 875K Check-Ins.” To the extent that surveillance is opt-in, it is far less worrisome than when it’s built into the infrastructure, or forced on consumers via contract revisions.