Privacy is back in the news with a ruling by the U.S. Supreme Court concerning the use of GPS devices attached to vehicles by the police without a search warrant. Whether we like it or not, as genealogists, just like the police, we are all in the privacy business. The case, if you are interested, is United States v. Jones. Beware, this is a pdf download. Anyway, the issues in that case was whether or not the Government’s attachment of the GPS device to the vehicle, and its use of that device to monitor the vehicle’s movements, constitutes a search under the Fourth Amendment. The Supreme Court held that it did and that attaching GPS device requires a court issued search warrant.
The part of the ruling that has an effect beyond the narrow area of GPS tracking devices is found in the wording, "Our later cases have applied the analysis of Justice Harlan’s concurrence in that case,which said that a violation occurs when government officers violate a person’s “reasonable expectation of privacy,” id., at 360. See, e.g., Bond v. United States, 529 U. S. 334 (2000); California v. Ciraolo, 476 U. S. 207 (1986); Smith v. Maryland, 442 U. S. 735 (1979)."
Admittedly, the case is couched in terms of the Fourth Amendment prohibition against unreasonable search and seizure, and is limited to government action, but the discussion in the media subsequent to the case pointed out that the issue could arise in the context of a Facebook account or Google Latitude. There are several other social networking applications that essentially broadcast a user's geographic position to the world. There is also a possible issue with GPS photographs, but that is likely a stretch.