Google stores your wifi password if you have an Android phone and sign into it. It stores it in Google’s servers.
According to Bateman, Google uses this information in its setup flow for new and factory-reset phones. Signing in to your Google account will download all of your stored Wi-Fi passwords, along with your contacts, calendars, apps, etc.
In theory, this is a fantastic idea. One less password the user has to enter, one less possible point of frustration.
But, consider for a moment:
Have you visited a friend and joined the Wi-Fi network in their home? Have you had guests over and allowed them on your Wi-Fi network so you could watch that hilarious Harlem Shake parody video? Maybe you’ve visited a small business, whose owner lets you onto their company Wi-Fi network because they aren’t savvy enough to set up a guest network.
My point is, you could potentially have dozens of Wi-Fi passwords on your phone, many of which are not your own, which are now—thanks to Andriod—stored on Google’s servers.
At least we can rest assured that Google doesn’t have a history of controversial behaviour related to harvesting information from Wi-Fi networks.