Nothing about the Fediverse prevents the corporate overlord A.I. bots from crawling it and using the data to track us. It doesn't matter if you haven't explicitly revealed your identity. Throw sufficiently powerful analysis tools at an account's post history and you can fingerprint it. Now do that with another account on another site. If the fingerprint is similar, it's probably the same person.
Best thing you can do to minimise the risk of that with the tools we have today is to opt out of search engine indexing in your Preferences. Also, decide if letting other people see who follows you and who you follow, because that's also possible to opt out of, and will give the crawlers less data to work with. Finally, you might want to consider if you should set the default privacy level to Followers Only. It might work better on a psychological level to explicitly mark Public posts as such.
@thor it's already happening. Cloudflare even has bots.
@thor I have a family-only Mastodon instance where only followers can see our posts, we all just follow each other. I do have to instruct new family to change a few settings to keep it private. It's nice - when I went on vacation I posted dozens of pictures per day to keep family up to date on what we were up to. I never got an ad or a mailing or some shit about where I was and the people I REALLY give a shit about got facebook-like notices on their phones and so on. So far I love it.
@bifpowell are those settings all client side? Does am app change or reinstall present the opportunity for leakage?
@jco42 It's all server side settings - I can definitely see a bug from an update or something screwing all that up sure - software sucks, and yeah, I imagine an app on a phone or something could leak stuff from it to the carrier or google/apple. I just presume everything is all gummed up.