That said, Google still indexes content from the Steem blockchain, so the "big data companies" can still build their picture of you with what you post here too.
All they need is some way to link your Steem profile(s) with the data they already hold, and your every post, and every comment gets added to what they already know.
The truth is, this loss of privacy is the price we pay to use these "free to use" platforms. When you look at the big picture, it's scary, but we don't look at the big picture when we're living out daily lives - we like convenience, connecting with, and interacting.
From a personal standpoint this doesn't worry me, because I'm always conscious of what I'm sharing, and how it's being used. But a lot of people put every tiny detail of their lives online - and just like a blockchain, the Internet has a very long memory.