An anonymous reader writes "Recent media reports indicate that in 2005-06, the FBI went trawling through grocery store records in order to track down Iranian terror cells. They hoped to locate 'Middle-Eastern terrorists' through the purchase of specific food items. Many of these items, though, are not sold through big-box supermarket chains, and the majority of mom and pop ethnic markets do not have the detailed computer purchase histories that Safeway or Whole Foods have. What the FBI seems to have done is instead put together a list of everyone who shopped at a Middle Eastern food market. All signs point to the credit card companies providing this data, and not the individual stores. If so, this could be the tip of a (potentially illegal) data-mining iceberg."