You can guarantee there has been instances in the past where information not favorable to governments/agencies/groups/powerful individuals has appeared online, whether thats skunkworks/black projects, state secrets, personal details or other highly sensitive information. In cases like these one could ponder if there is a cleanup team dedicated to scrubbing every trace of any sensitive info, perhaps crawled by extremely efficient and powerful AI. Giving in to this fantasy (I enjoy sci-fi, sue me
), I picture them feeding this all powerful motherbrain type AI encrypted arrays of data relating to projects that would take billions of years to brute force and can only be efficiently unlocked by the central AI. Anyway, back on point - with a web ran on the blockchain even with this fantastical AI, there would be no means of removing this data? You cannot duplicate and swap a blockchain or could you if you had access to the majority of computers running/mining it?
So tldr: how will highly sensitive information be contained and what options (in theory) could governments and agencies devoted to containing this information utilise to scrub said data? I suspect no matter what anonymity tech a decentralised web uses they will find a means to identify individuals leaking data eventually, but removing information that needs to be scrubbed within minutes/hours?...
Bit of a ramble