http://blog.nowherejezfoltodf4jiyl6r56jnzintap5vyjlia7fkirfsnfizflqd.onion/opsec/anonymityexplained/index.html
Google, who let's say has been watching your search history and browser info, learns that you are in New York City, in your 20s, male, skii, and love cats. There will be very few people who meet this whole criteria, but Google obtains this information for advertisement targeting.