Per Wired, 22-year-old programmer Aaron Swartz has been investigated by the FBI because the Government Printing Office experimented with offering free access to its database of public court records, and Swartz made the mistake of accepting their offer.
Swartz downloaded 19,856,160 pages, uploaded them to amazon.com's EC2 "cloud" service, and donated them to public.resource.org, "an open government initiative spearheaded by Carl Malamud as part of a broader project to make public as many government databases as Malamud can find. It was Malamud who previously shamed the SEC into putting all its EDGAR filings online in the ’90s, and he used $600,000 in donations to buy 50 years of documents from the nation’s appeals court, which he promptly put on the internet for anyone to download in bulk."
Prior to the GPO's experimental offer, the records had been available only for a fee of 8¢ per page, or more if purchased through a privately-owned, commercial intermediary. When the gummint figured out what was happening, they abruptly terminated the experiment and notified the FBI that the database was "compromised."
A partially-redacted FBI report shows they ran Swartz through a full range of gummint databases, among other things checking his work history, his Facebook data [see, e.g., here and here], whether his cell number had ever come up in a federal wiretap or pen register, and checking him against a private data broker’s database; they also obtained his driver's license photo and considered a stake-out of his home (which they concluded would be too conspicuous, since few cars parked on Swartz's dead-end, suburban street).
"The feds evidently identified Swartz in the first place by approaching Amazon, which provided his name, phone number and address. . . . Amazon’s user agreement for its cloud computing solutions gives it the right to turn over customer information to the government on request."
More at Wired. (And for more on Amazon's role, see Amazon EC2 and Amazon VPC.)
(Thanks, Ben!)