[_delirium]

Was it in one of the more "magazine-style" publications, like ACM Queue or CACM? I believe those have a more active editorial staff, as compared to stuff like ACM Transactions on Graphics, which requires authors to prepare a publication-ready PDF, with no ACM-provided editing or formatting assistance.

My only personal experience with editorial "assistance" is with an IEEE journal, which totally messed up one of my articles in a way I didn't notice until it had gotten published. They had moved the "related work" section to a sidebar inset, and since I'd read that section a million times I just assumed it was the same (in new location) and didn't read it closely again. Turns out they helpfully reorganized some of the references and discussion of them, so it no longer made much sense, and even had newly introduced grammatical errors.

[scott_s]

I have published in ACM and IEEE conferences, as well as had an article in IEEE Computer. The experiences are very different. The conference paper was all us - formatting, editing, everything. The article in Computer we had multiple iterations with a professional editor whose job was to maintain a consistent "voice" throughout the publication.