Why protect yourself?
Google logs and analyzes so much information about a chrome user's browsing habits, it can tell who they are, out of billions of people, without even needing them to log in most of the time. A lot more than targeting an advertisement can be done with your browsing history and info which is stored indefinitely. Along with the companies that pay to access this info, random google employees/contractor, hackers, or even government representative with no warrant can access it, and potentially know you better than you know yourself.
With that said, the browsers that don't log user info also aren't safe. Most sites, and the advertisements on them run so much javascript they don't even need to have access to your browser's source code to track your browsing habits, and build psychological profiles.
What happens to all this data? Some is used to build profiles for highly profitable targeted advertisements. For example, the department store Target uses a system to identify pregnancies, using simple inputs like buying unscented lotion, and other small innocent factors. They can predict with a great degree of accuracy when a woman has entered the 2nd trimester of pregnancy. They send her targeted coupons so she'll start buying things like diapers and potentially become a lifelong repeat shopper at a time when her spending habits have the greatest potential for change.
Other things can be done with your browsing/shopping data. For example, if you pissed off the wrong person in the government, your data can be used to build a profile and find anything possible to against you. Roger Ver once made a speech condemning the ATF. Little did he know there was a group of ATF agents in the audience. They basically investigated him by building a profile of all his online activity, found he was a prominent Ebayer and looked at everything he sold, eventually finding commonly availiable firecrackers that he sold, commonly used to scare of birds. This somehow violated a bullshit law and they ended up using this info to send him to federal prison for a little over a year. Considering many ebayer's sold these, along with sporting goods stores like Cabellas wasn't important, this was clearly targeted enforcement.
Basically, everything you do online can also be used to build a psychological profile on you, and you can also be targeted for mind control techniques to influence your political views like in the Cambridge Analytica scandal.
With that said, protecting yourself from data collection is more important than most people realize.
Protecting Yourself 101:
Download and use the Brave Browser, it blocks all advertisements by default, no plugin needed. Unlike Adblock, it doesn't sell a backdoor to advertisers to circumvent their block and serve you the advertisements, and deliver harmful tracking scripts. It blocks everything by default which can sometimes fuck up the way a site works/looks, but you can obviously choose to lower your shields if you trust/need the website that's fucked up. They even have iphone/android apps.It also uses https:// everywhere it can as opposed to http://
Erase any unnecessary personal data stored by google by going here: https://myaccount.google.com/dashboard It will give you a list of google services you use, go through and delete anything you feel isn't in your best interest for them to have.
Stop using spyware like Google Chrome/Safari, and most other browsers that send google/apple your data in the background. Even Firefox is questionable these days and the need for add ons like ad blocking software etc. lowers the chance of spyware being slipped in.
If you must use social media, try to keep your accounts unlinked, and for gods sake delete any app from your phone that you're not using. I have a special browser I use that's built into my password manager on my phone that I'll log in and out of facebook if needed,. The app itself sends data in all day, even when you're not using the app.
Keep unnecessary apps to a minimum on your mobile. There's currently a lawsuit against Bose(I should get in on it) because they used their iphone app to listen in on your conversations via bluetooth connection to make a little extra money on the side selling their customers data for targeted adds. Ever had a conversation about a topic and get an advertisement for a related product immediately afterword?
Start using duck duck go as your default search engine. It's as good as google 99% of the time but without the intrusive strings attached, and without logging your data.
If you look at anything like anti government sites, anything involving illegal stuff like the dark web, or something you don't want to run the risk of the government, your ISP, or anyone else finding out use TOR, what TOR is is complicated but I've dropped a video below that explains it more.
Use a VPN, I'm using Nord VPN, paid $99 for the 3 year plan and can't complain.
Protip: If you're using the brave browser just click: [ File > New Private Tab With TOR ] and boom, you're now browsing using TOR.
Brave Browser:
A video explaining the future features coming to the Brave Browser:
I'll probably edit this later to add/clarify some points.