Maybe the post is not identical to one used before, but the technique is identical. Take half a dozen paragraphs from an outside source, toss in a few phrases of expansion and comentary, and suddenly it's yours. I wonder if this works on college essays when they are checked by internet robots.
It might slip by if you're checking for the whole sentence, but maybe not if it's specific phrases you're searching for. In any event, when it's discovered, the intent to steal by changing a word here and there becomes obvious. At least if you copy word-for-word, you can always claim that you innocently "forgot" the footnote. But this doesn't really save anyone.