MS Office and Open-/LibreOffice are using zipped xml files (e.g. .docx, .xlsx and .odt). Svg vector graphics is xml, the x in ajax stands for xml (although replaced by json by now). SOAP (probably counts as the predecessor of REST) is xml-based.
XML was definitely popular in the "well used" sense. How popular it was in the "well liked" sense can maybe be up for debate, but it was the best tool for the job at the time for alot of use cases.
"After ten years in print, our publisher decided against further printings and has reverted the rights to us. We have published Elements of Programming in two forms: a free PDF and a no-markup paperback."
Reminds me of the quote by Kent Beck (allegedly):
"Make it work. Make it right. Make it fast".
First throw something together that works, then refactor it to make it "right" (clean, readable etc). Finally optimize it if it's necessary.
Like the author of this article describes it "Write more bad code. [..] Get answers. Learn as much as you can about the problem you’re trying to solve [..] it’s much faster in the long term to write bad code then make it good, than to try to write good code in the first place" https://medium.com/swlh/coding-faster-make-it-work-then-make...
Maybe I didn't make myself clear, but the image in the article looks like it could have made both one and two passes through a Xerox machine before it ended up in the paper.
I wonder if you could get the same unexpected result when copying images of Western blots?
It's probably not the case here but it could be devastating for a researcher to be accused of fabricating data by using an affected copier/image editor/file format.
XML was definitely popular in the "well used" sense. How popular it was in the "well liked" sense can maybe be up for debate, but it was the best tool for the job at the time for alot of use cases.