The second paragraph of that post reads, in part:
… over the coming months we’re expanding close variant matching to include additional rewording and reordering for exact match keywords.
Sure enough, AdWords indeed intends to change the way that exact match behaves.
The change allows AdWords to (a) ignore function words in a query, (b) ignore function words in an exact match keyword, or (c) match what it deems similar intent function words.
With unique queries, it’s unlikely that an advertiser would have added those keywords to its account, since the queries would not have shown up in search query reports and keyword tools.
There were a few issues where plurals had different meanings, but all in all it simplified keyword build-out.