I don't even want to think about the beers I'd have to buy if a human were to be tasked with reading what my 20 yr old self thought was important enough to bray about in 1992. I shudder to think.

My assumption has always been that there's too much data for the vast majority of cases to get anything more than automated analysis.

The storage is the problem, not the analysis. After all, if anyone does anything notable, all their past conversations (public or private) can be pulled up for retrospective analysis. That's why anonymity on the internet is a mirage - better to assume that public postings can and will be used to construct a complete history of you at some point in the future.