It's an interesting one. Twenty years ago I wouldn't have given this any real thought, but today logging in to someone's daily driver laptop, or their smartphone is opening a window into their inner lives and thoughts (authentication notwithstanding) - maybe it's just this century's version of discovering someone's stack of diaries in the 1900"s.
Aside from YouTubers (other platforms are available) buying rando e-waste off eBay and trawling through hard drives to see what's on it, maybe there'll even be people dedicated to looking through personal devices to find out what happened up to a certain date in time. The data's there to be revealed, after all.
For me, it'll probably end up with "man he was boring as fuck, but he did love a meme".
On a brighter note - someone released a great game called Last Seen Online covered by AlphaBetaGamer which was very, very well done if a little janky in certain areas. Peak early-2000s nostalgia for this sort of thing, angsty popups and everything.