Among articles you see on the front page, there is a two orders of magnitude difference in visits between the more popular and the less popular.

HN/reddit/twitter/android can all send a similar amount of traffic. There's one order of magnitude there, how many places an article is featured at the same time?

Then there's an order of magnitude within each place, how much interest and readership the article could gather? Highly variable. The first comment alone can make or break an article.

This sounds off. Both reddit and twitter have the potential for vastly more traffic than HN.

I also haven’t had the number one spot on HN (except maybe briefly), but was in 2 and 3 for long stretches and even an order of magnitude more traffic wouldn’t have been a problem.

Two orders probably would have been, but I have a hard time imagining a 100x traffic difference between the 1 spot and the 2 spot. Then again, if it was a very slow day here vs a very busy day maybe (though in my case it wasn’t a very slow day).

I assume you're targeting reddit programming and similar subs, they're similar to HN in aggregate. You're right that Reddit and twitter have way bigger audience in total but only a fraction of all reddit users is relevant. Assume we're talking about a tech blog, not articles on election or brexit?

It's not about rank. It's about the specifics of the article, mainly the title and the content. It simply attracts more or less readership.