This may stoke the flames of paranoia or "Big Brother" is listening, or insert your favorite political conspiracy. Go to Google.com (the search page). In the search window is says "Say OK Google" where you can also type your query. Say those words, wait for the tone. Ask the question and it searches. So basically your mic is always on, with no input from you turning it on, listening for "Say OK Google"...you got to wonder what else is being captured. I have an iMac and assume it works with Windows, too.