The rapid consistency of these posts and them being about something so benign makes it seem like Meta is posting these to HN for publicity.

Yeah, I'm sure meta is just dying to get publicity on this tiny site.

2M -> 5M = 2.5x

5M -> 10M = 2x

10M -> 30M = 3x

Counting at exponential intervals is fine and notable.

Maybe exponential intervals are better than linear indeed. But your remark is orthogonal to parent's complaint that the updates are simply too frequent: to take your exponential framework, they would probably prefer a x100 interval before the next post rather than a x3.

Assuming we see a new post about Threads user growth at x2 intervals, we'll see a maximum of eight more posts before they run out of humans.

And would all of these posts be useful information?

The comments would be. They'd be a nucleus for the latest findings about Threads. For example, in the comments of the most recent one I found out that although you can deactivate a Threads account, you can't delete it without also deleting the linked Instagram account. That's useful to know.

You really don't need these submissions for that purpose, because it's all over the news:

Threads profile can only be deleted by deleting Instagram account, Meta says https://news.ycombinator.com/item?id=36612434

Threads profiles can't be deleted without removing your entire Instagram accounthttps://news.ycombinator.com/item?id=36621526

You can't delete Meta's new Threads app without deleting Instagram too https://news.ycombinator.com/item?id=36627712

You will later be able to delete your Threads account with o losing Instagram https://news.ycombinator.com/item?id=36630147