That is actually kinda fascinating given that it's directly in opposition to this blog post. I wonder who's telling the truth?

This seems very unfair. There's absolutely no point, anywhere in that IA blog post, that says "We found it". Anywhere! They're just providing information on the history of the file, from their archives, and detail into why it's an amusing story.

They even say

Naturally, as news of the Backrooms being “found” travels throughout the world, responses have wildly ranged. For some, this is a proof that “with enough eyeballs, all problems are shallow”.

How is that taking credit?

I think it’s usually pretty customary to attribute the original source if you’re going to write an exposition. They go through enough work explaining exactly the location of the furniture store, you’d think they’d have the courtesy to link to the tweet which actually made the discovery.

As has been pointed out though, IA has a pretty tenuous relationship with the Musk/chan adjacent parts of the internet, so it doesn’t surprise me they deliberately left those facts out.

You say that as if anyone knows.

From other comments in this thread, it looks like some guy on X solved it in 2018, yet others had no idea, and solved it independently too.

How many others "solved it"? Where is the official record of this? Who really was first? Did someone solve it before 2018? Did more than one party solve it, independently, recently?

Trying to untangle that and be sure, isn't simple.

They covered this by saying many eyeballs solved it, and then went on to their key message, highlighting the importance of archives, and showing how their archive proves the solution is correct.

My point is, pointing an accusatory finger at them, and saying they are trying to take credit is not fair.

The people who found it are telling the truth. The trail of discovery was 4chan then Twitter then Wayback Machine.

The legend lives on :)