Could be that.

Could be big data. If you click a link to furaffinity on Bluesky, this change means they know your account visited that website, and they know you're a furry. So they sell that data to Fursuits-R-Us. Then Fursuits-R-Us buys some feed priority with furry users, and now you're seeing a lot of posts about Fursuits-R-Us. Ta-da, that's the magic of feed-integrated personalised advertising. You get marketed to, and you don't even know it.

You might think advertising fursuits is harmless. But what if The Heritage Foundation buy that data and that feed priority instead? Or what if a right-wing Twitch streamer just started a playthrough of Red Dead Redemption, so they pay Bluesky to promote their content to all accounts that are marked as politically naive Red Dead fans?

This is how elections are bought and sold.