Good luck with that. It is trivially easy to ‘unmask’ someone if you have the right data. For example, if I have your IP address, I can see that user ‘eschereal’'s IP logged into a bank computer, then did a POST to twitter, then did another POST to facebook… By analyzing timestamps and patterns, I will soon know exactly who you are. Add in data from AIs looking at writing style fingerprints and common subject matter analysis and all kinds of other tools, and soon I can track you around the internet even if you use VPNs and all manner of ways of hiding your activity.
Perhaps a real security expert who stays on the ball can remain anonymous. For the average person, just a slipup here or there by you or the site you are using will burn you.
For example, my email address/password have shown up in 42 hacked dtabases, according to google. Let’s say one of them was the sdmb. Now ‘Sam Stone’ is publicly tied to my personal email, as well as my IP address, Anyone with that data (and the data in 41 other databases) has a huge collection of text they can use to annalyze my writing, common typos, etc, and use that to track me wherever I post, with a good degree of accuracy, no matter how much I try to hide my identity.
Remaining anonymous on the Internet is almost impossible if you have been on long enough and people really want to find out who you are. And as the tools get better, it will become more common, or even a casual thing to do an identity search and discover what you do online even if you are trying to hide it.