At the beginning, Google used to be just a search engine. Most certainly, you still use google majorly for that purpose. Now, Google collects your data in order to improve the search engine for you and as part of their core business of advertising.
Your search history says a lot about you. For google to attach your search history to you, one needs to have a google account. This is your Gmail account which logs you to YouTube, Google Calendar, Google+, docs etc. With your browser logged in, check out https://myactivity.google.com/myactivity to know how much of your search history Google has. It is quite amazing and freaky at the same time that Google will remember what you searched for 2 years ago while you don’t.
Next, head to https://www.youtube.com/feed/history/search_history to see what you searched on YouTube and see your YouTube watch history.
Google collects all these data in order to successfully target you with advertising. This pays for all the free services you get to enjoy. Depending on one’s perspective, this is a sinister tool or just a cool way to get free stuff.
You will probably see a different set of adverts when using your work email as opposed to your personal email address. An engineer will see engineering-oriented adverts while using the work computer and see broad-based adverts when logged in using a personal email. One can opt in or out of internet-based advertising by google. I prefer to remain with mine as it gives me stuff I would want to see anyway. An option to opt out is in the Google analytics opt-out page.
There is an option for google location within the Google dashboard. When turned on, Google keeps track of your location and tailors results based on location. This is mostly done within android phones. You can check out where you have been from https://www.google.com/maps/timeline?pb
Do you use Chrome or androids default browser? Chances are that you have most of your password saved on the cloud. Most people don’t realize this until all your accounts are hacked. You can disable AutoSaving passwords and just stop saving them when you log in. Just head to https://passwords.google.com and see how many of your passwords are online. There is an option to delete the passwords and prevent google from saving more.
If you use your android phone, there is a high possibility that your contacts are synced to google servers. I find this feature important as it helps in the sorting of contacts especially when you have multiple duplicate contacts. It also serves as a backup tool in case you lose your phone. You can enable/disable this by changing your mail sync setting on your android phone. Check your contacts at https://contacts.google.com/
Google introduced an About Me tool that lets you see what information other people see about you. Any changes made at this tool will be mirrored across all google services. Visit the tool at https://aboutme.google.com.
Google knows much about every one of their users. It is important to control what information about you is online. Keeping a safe Gmail account is the safest way to secure your already archived information. Please change your password from your pet’s name to a more complex multi-type character password.