In 2016, Princeton University conducted a large-scale study on online tracking, and concluded that at least 75% of all websites contain tracking code used by Google, mostly for the AdSense and Analytics services. That doesn’t include the various other similar trackers used by social media sites, marketing companies, and online merchants.
Even if you don’t use Chrome and aren’t signed into a Google account in another browser tab, you’re still tracked via unique identifiers, which are similar to license plates for vehicles. They’re alphanumeric strings that correspond with a specific device, app, or browser. Ostensibly these are used to save preferences such as a time zone or language setting, or various search settings. By themselves they don’t typically identify you personally, they just identify your phone, tablet, the browser on your computer, or your activity on YouTube when you aren’t signed into an account. Just like with license plates, though, a unique identifier could be combined with other data to connect those devices, services, and activities to you. Google doesn’t say whether or when it attempts to connect unique identifiers to people; all it says is that it creates them and uses them to collect short-term data when someone isn’t logged into a Google account.
When you are logged into a personal Google account, here’s a detailed breakdown of what Google collects and tracks:
- Whatever you put in your profile: This includes your name, email address, phone number, Android devices, and payment information.
- Whatever Google’s corporate customers give them: Marketing partners, advertisers, researchers, and security providers can give Google any information they have about you, and Google will collect that if it can.
- Public information about you: If your name appears in the Google search index—for instance, if you post your resume to a job board, have a public social media profile, or are interviewed for a newspaper article—then Google collects it and can associate it with you.
- Everything you say: All voice and audio features may be recorded and analyzed, including actual recordings of your voice if you perform a voice search or use Google Assistant. If you use Google Voice, literally everything you do with it is collected.
- All of your SMS text messages: If you use any of Google’s apps for SMS, Google collects the messages, recipients, timestamps, and other content.
- Device, app, and browser metadata: Google collects information about every device and browser that you use with any of its services. The depth of this information varies, but can include the browser version, operating system version, mobile carrier and phone number, mobile device model number, IP address, screen resolution, crash reports (if an app or browser crashes while using a Google service), a list of installed apps, and other similar data.
- Search history: All forms of search across all Google services is recorded.
- Purchase history: All purchases from the Google Play Store, or via the Google Pay app, are collected.
- Ad interactions and mouse movements: If you click on or otherwise interact with an ad, Google records the context around it. Mouse cursor movements on or near ads, and even interaction with non-ad elements on a SERP or other page or service with Google Ads may also be recorded.
- Contacts and email addresses: Previously Google analyzed the content of your email and served ads in the Gmail client based on what it recorded. Google claims that it no longer does this; instead it uses the normal ad personalization algorithm based on your Web activity. However, Google does analyze your Contacts list and the to/from fields in emails, to provide recipient suggestions when composing a new message.
- YouTube: Your search history, watch history, lists, subscriptions, all of the videos you’ve uploaded, all of the comments and votes you’ve made, and anything else you do on YouTube is collected.
- Location data: In Google Maps and Waze, your driving directions, navigation routes, pins, and favorites are all collected. Furthermore, a variety of location information (such as your IP address, nearby wi-fi access points, cell towers, Bluetooth connections, GPS coordinates, and any other sensor data) may be collected by any Google apps or services that have access to it.
- Drive: Everything stored in Google Drive is collected by Google, including all documents, images, and other content.
Much of this doesn’t apply to Google Workspace and Google Cloud Platform accounts, which do not have any advertising, and have stricter privacy controls.
Privacy is extremely important to me, so I added a whole chapter to Google Power Search to explain what Google collects about you, how it uses that data, and what you can do to delete it and prevent Google from collecting it again.