However, Apple says the data is anonymised after six months so Apple doesn't know exactly who asked what.
Apple spokeswoman Trudy Muller explained to Wired: "Apple may keep anonymised Siri data for up to two years. If a user turns Siri off, both identifiers are deleted immediately along with any associated data."
When you speak to Siri, it squirrels your voice data off to Apple so the company can analyse it - but associates it with a randomly generated identifying number rather than your Apple user ID or your email address.
After six months, your data files are disconnected from this random number, and after another eighteen months the voice file is deleted.
The company says it uses your voice data to test features and make upgrades - but if you've been telling Siri all your secret hopes and fears (or just revealing your otherwise-hidden love for fried chicken or something more embarrassing) then it may come as a shock to know that some Apple engineer could have listened in.
Siri is only just now approaching its second birthday, so everything you've ever confided in it is still accessible.
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Former UK News Editor for TechRadar, it was a perpetual challenge among the TechRadar staff to send Kate (Twitter, Google+) a link to something interesting on the internet that she hasn't already seen. As TechRadar's News Editor (UK), she was constantly on the hunt for top news and intriguing stories to feed your gadget lust. Kate now enjoys life as a renowned music critic – her words can be found in the i Paper, Guardian, GQ, Metro, Evening Standard and Time Out, and she's also the author of 'Amy Winehouse', a biography of the soul star.