False Positives and Ubiquitous Surveillance Searching on Google for a pressure cooker and backpacks got one family investigated by the police. More stories and comments.
This seems not to be the NSA eavesdropping on everyone's Internet traffic, as was first assumed. It was one of those "see something, say something" amateur tips:
Suffolk County Criminal Intelligence Detectives received a tip from a Bay Shore based computer company regarding suspicious computer searches conducted by a recently released employee. The former employee’s computer searches took place on this employee’s workplace computer. On that computer, the employee searched the terms "pressure cooker bombs" and "backpacks."
Scary, nonetheless.
EDITED TO ADD (8/2): Another article.
EDITED TO ADD (8/3): As more of the facts come out, this seems like less of an overreaction than I first thought. The person was an ex-employee of the company -- not an employee -- and was searching "pressure cooker bomb." It's not unreasonable for the company to call the police in that case, and for the police to investigate the searcher. Whether or not the employer should be monitoring Internet use is another matter.