After releasing Siri on the iPhone 4S back in 2011, Apple has finally disclosed how long it keeps all of those commands and hankering questions you have for Siri. The Cupertino-based company says that it keeps all Siri data for two years, but they state that all of the data from Siri that the company collects is completely anonymized.
Wired details the process of which Apple uses to anonymize all Siri data. Essentially, all Siri commands get sent to an Apple data farm, where Apple generates a random number that represents the user and associates the Siri commands with that random number. After six months, your random number is deleted, but the Siri data remains intact until 18 more months have passed, where the data will then get deleted.
The ACLU says that "what you say to Siri could reveal sensitive things about you, your family, or business," and they warn Siri-wielding folks that "Siri works for Apple, so make a note to yourself to really think before you speak." In a day and age where privacy is a big issue, some users can still easily overlook how much data they're giving away.