Is there a way to scrape reviews and build an accurate database of all reviews over time that is verifiable by some blockchain type of encoding so you know if they were modified or deleted and can do a check against the current site.

This would yield far more insight than taking their word on their proprietary algorithm flagging reviews. This would also be awesome to use against Yelp that I have first hand experience trying to be extorted by their sales teams affecting a family small business I host a website for and yelp page.