I really enjoyed this. I wasn't into Tumblr in this era, but I've watched enough of a YouTuber to have an idea, and I think you nailed the feeling. At the very least I can instantly tell it feels like the internet in that era. I see myself massively in Karla, in like every action. It, it made the story more real. All of the little things did that. Everyone had a distinct realistic voice and it had the bad uncomfortable stuff, it just sells it so well. I don't know what more to add. I read the postmortem, so I know you're kinda conflicted with how it turned out, but I think it did what was intended better than anything else could.
Oh, and you may find it interesting, I was pretty conflicted when trying to come up with a blog name. I just couldn't think of anything. But, then a line from a song I like popped into my head, since I use it as the "about" for my discord account, "And the wind I know it's cold", so I went with that and really liked it. Felt very Tumblr. Then I ended up turning out to be a Keeper of Wind who likes Luna, the Auger of Ice. So clearly it was fated. Also I now use it for my actual Tumblr, to fit the aesthetic of the site more than my previous one :)