Hi Joe -- I suspect the "movement" will happen if SI shuts down. I feel the same way you do -- SI's public messages are a time capsule of the stock market and internet boom from 1996 - present. From a research/historical perspective, these messages (in aggregate) are worth a bunch of money.
Ummmmmmm ....... I hope the private messages are purged regularly, lol
I think the SEC should buy the database if it even goes up for sale !