I'm Old, and honestly think you should consider holding onto your social media accounts even if you don't want to use them anymore.
I think the Indieweb is a super interesting project and it definitely does resemble the Internet I spent my childhood and teenage years on more (1997 - 2007, let's say). I'm trying to spend more time on this and less time on conventional social media, which is what "the Internet" is for most people. But for a lot of people, that social media is where they spent their childhoods on and though the companies are definitely evil, your content isn't and I do wonder if people might someday regret totally nuking it all.
A lot of the old Internet still exists and I occasionally revisit my profiles on Fanfiction.net or LiveJournal and see what I was posting, gosh, more than 20 years ago. Doing that you sometimes find new stuff too. Like apparently somebody went and translated a lot of fanfiction I wrote into Russian?? Wild stuff! A lot of these entries basically serve as diary entries, too, and of course there is plenty of shitposting with friends.
It can be kind of embarrassing to look back on that kind of thing if it's your recent past but when you're 40, like me, and don't talk to many of those people and certainly don't have those same problems and interests anymore it's still nice to be able to look back at it. I was never any good at keeping a paper diary, but I sure was good at posting.
One of the first things I put on the Internet was a Mary Sue fanfiction for Star Trek: The Original Series. Not only did I write myself in, I wrote my brother in too, and many years later I found fragments of a handwritten sequel he'd penned himself (which he probably doesn't even remember anymore) of his own character going off on future adventures. Of course by the time I was 16 or so I considered this fanfiction pathetic, and I deleted it in shame. I so wish I still had it, which started about ten years ago, but it is unfortunately irrecoverable.
I still toy with deleting my Reddit account or Facebook or other social media accounts I've used and abandoned, but I feel like future me, maybe sixty years old, will regret losing those bits of writing and evidence of my once-interests. People from long ago also sometimes contact me on these platforms! I only get to it months later but if they are interested in talking to me that still counts.
Obviously yes, this is a privacy risk. It is not a huge risk though, and there are benefits too. It also benefits those evil companies to leave it, in a very marginal way, and I understand those concerns too, but you might find the value to you greatly outstrips that concern down the line. It's worth thinking about, anyway!
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