Eh, it's not so much that it stopped working as it is that it never worked the way you thought it did.
Quotes have ~always been an exact match on the tokenized query text, not a substring match on the corpus text. No synonyms, reordering, gaps, etc, but the matches -- and failures -- are sometimes not obvious at first blush.
If you search for "don't stop me now", for instance, that "don't" tokenizes to "don t", so it will match the tokenized strings "don't", "don t", "don-t", "don, t", etc ... but not "dont", because that's outside tokenization.
On the other hand, snippets mostly are substring matches of the query text, so if you see a result to a literal query that doesn't have a snippet, you know it's probably one of the weird matches.
This is just patently false in addition to being condescending.
If you use quotes around a phrase, it will reorder terms and make substitutions with synonyms in addition to straight up ignoring the quoted phrase no katter how many times you add +. If you then fiddle with settings (randomly not available depending on star alignment and device) to change it to 'verbatim' it will still reorder and split up tokens in the phrase.
In the past that Google search returned no results for any search. Today the set of results are altered before they are presented to the user. Sometimes the set of reslts is empty and at other times it contains results.
For example:
steve -steve returns 0 results
test -test returns 4,780,000,000 in my search
starting with google/youtube videos
That's easy; there are synonyms added for test but not for steve.
If you search for ["test" -test] you'll get no results; quoting "test" removes the synonyms.
It's probably not new behavior per se, but synonyms have gotten a lot broader over the years, so it was a lot easier to punch [term -term] ten years ago and hit a term which had no synonyms.
Correct, though it is new in the sense of this conversation, which compares to how a search used to be.
The point wasn't as to what the synonyms were for a specific search term but that they have been added as implicit terms, which makes google search no longer exact.
I mean, I'm confident that the core of how it works -- "an exact match between the tokenized document and the tokenized query" -- hasn't changed in a very long time, but I can't really promise there wasn't another aspect I'm ignorant of that is responsible for the behavior you remember that changed somehow.
"Exact tokenized matching" can look like "exact string matching" a lot of the time. Until you hit some of the edge cases it's like kerning: https://xkcd.com/1015/
