Apple recently revealed the fact that they keep all Siri inquiries stored on their servers for up to two years. That's right, every question, comment or message spoken to the personal assistant gets anonymized and archived to improve the service, according to Apple spokesperson Trudy Muller.

The admission comes after Wired published a story about some unclear disclosures in Siri's privacy policy. The story itself came to light courtesy of American Civil Liberties Union lawyer Nicole Ozer who brought the issue to the publication's attention.

Here's how the process works, according to Muller. When you interact with Siri, the audio recording is beamed over to Apple's data farm for analysis. Apple creates a random number to associate with a particular user and their submissions. This unique identifier, which isn't your Apple ID or your e-mail address, represents the user's Siri submissions with regard to back-end analysis.

After six months, the voice clip in question is disassociated with the user. The clip is then stored for up to 18 months to assist Apple in testing and improving the product. It's worth pointing out that if a user turns Siri off, both identifiers are deleted immediately along with any associated data.

It's the first time that Apple has revealed how long they retain Siri data although the ACLU lawyer said Apple could do more. She believes Apple should link to Siri's privacy policy on the service's FAQ. What's more, since everything is archived, she suggests people should be careful about what they say to the personal assistant as it could contain sensitive information.