Hello, smart people. Filling out an online form to volunteer for something, Firefox's Facebook-fence icon appeared on the email field. Confused, I clicked on its question mark. On the next page, Mozilla wanted to sell me Firefox relay for $7/mo. (That's their VPN + email masking + phone masking.) I used my yandex.ru email address instead for $0. Here's the question: is Facebook really able to track me because I've signed up to volunteer for Cornel West (setting aside the FB-Russia blockage issue)? Thanks.
Oh yes. The "like" buttons on websites are also used for tracking people, so any website that is Facebook-enabled will know who you are. Additionally, browser fingerprinting makes it difficult to stay anonymous, even without an account.
More or less, it's the worst-case scenario. Governments of many countries have sued and fined the crap out of them for obtaining data in a way that is illegal. But they make so much money with that data that they almost ignore the concern.
Related to fingerprinting, it's theorized that if a person doesn't have a Facebook account but their friend group does, Facebook will create a "shadow account" which isn't public but still attempts to collect data for this person based on the posts, pictures, and location data from friends on Facebook that spend time with this person. Zuckerberg admitted to Congress that Facebook does collect information on non-users.
Even for users, Facebook attempts to establish a lot of metrics, even if the user doesn't provide them, like estimated income and political affiliation, for advertisers to use.
I saw some of this first hand. Several years ago I tried some advertising for some affiliate marketing. Facebook's ad platform let me limit advertising to people with gaming consoles between certain ages, and I noticed I could target it for people who likely leaned more liberal or conservative if I wanted, or only for an estimated household income level. It's surprisingly detailed.
I presume that will at some point also include data scraped from the fediverse.
One thing that really does help, is salting your data. The online equivalent of wearing a fake moustache, is the occasional comment that may or not be entirely incorrect. I live in France. As a black woman, I support Trump. I'm expecting a baby. I want to buy a new house. That kind of thing.
Of course it does lead to minor inconveniences. For example, my google calender mentions my father's birthday being on the 13th of August. In reality we have the same birthday. My birthday is on the 18th of September. Once again, I'm salting the data. That way if I ever mention something factual, it'll be hard to tell which bits of data are or aren't real.
I'm exagerating for effect, but you get the gist. Occasionally change details or names a small bit to make your profile fuzzy and easier to confuse with someone else's.
User agent has quite a few things included, such as browser and operating system, so if you use a different browser, you’ll have a different user agent. The trouble with user agent is that some techniques used to try and make it more anonymous ironically make it easier to track. There’s not really a good option. Although it’s definitely worth getting a user agent switching plugin to disguise yourself as Google bot so you can bypass paywalls
Some browsers have proprietary APIs that break web standards (see Chrome), and sometimes, workarounds are needed for some browsers. Changing the user agent might break functionality.