・Everything Google knows about you (and how it knows it) | The Washington Post
If you have an Android phone, that device may log your location and velocity data. If you have a YouTube account, Google knows not only what videos you upload, but which you watch, too. There’s Google Maps. Google Play. Google Voice, if you use it to transcribe your missed calls. Between Google Contacts and Chat, the site has a pretty good idea who you’re friends with.
And while browsing data is aggregated differently than information from Google services, if you visit sites running Google Ads or Google Analytics software, Google also generally knows what you look at and what you click. According to one report from UC Berkeley’s School of Information, Google can track user behavior on 88 percent of all Internet domains.