[teraflop]

I certainly didn't intend it as a personal criticism, and if it came across that way I'm sorry!

There's nothing wrong with not knowing what ACH is and asking about it. But conversely, there's also nothing wrong with writing an article about ACH that doesn't bother to explain the background in detail, nor is there anything wrong with posting such an article to HN.

The only thing I take issue with is the suggestion that it's somehow unusual or noteworthy.

> In the future, you could just answer the question, or you could opt out of replying entirely.

I noticed that other commenters had already answered the question adequately, or else I would have included it in my response.

(For what it's worth, I just tried a Google search for "ach" in an incognito window with both region and language set to Germany, and two articles about the ACH system were on the first page of results. Again, I am not saying this to criticize for not knowing about it.)

[s9w]

Just for the record: I obviously could have googled it. But although I'm German, I spend a good amount of time in the "American internet" - and never heart of ACH. Plus the submission was upvoted like crazy. So I was pretty confident that this was either spam or I'm having a brainfart.

It seems though that there are things like ACH that are somehow very common knowledge but I've never come across until now.