I'm of two minds about this. One the one hand I certainly tend towards a preservationist mindset and as the sibling comment notes, we don't really know what we should save for various reasons. The guy who is responsible for having saved a bunch of Usenet archives made a comment to the effect of: "I didn't realize that what we really should have prioritized was discussions about social issues, culture, etc.--not bug fixes for a long obsolete version of SunOS."

OTOH, I'm kind of glad that nothing I wrote that wasn't filtered by an editor from before maybe age 30 or so exists online. (And even the filtered stuff you probably would need to know where to look.)