You may remember this case from Chemistry - A European Journal earlier this year, where a paper appeared whose text was largely copy-pasted from a previous JACS paper from another lab. This one has finally been pulled; Retraction Watch has the details.
The most interesting part is that statement "The authors regret this approach", which I don't recall ever seeing in a situation like this. The comments at Retraction Watch build on this, and are quite interesting. There are many countries (and cultures) where it's considered acceptable (or at least a venial sin) to lift passages verbatim from other English-language papers when you're publishing in that language. I can see the attraction - I would hate to have to deliver a scientific manuscript in German, for example, which is the closest thing I have to a second language.
But I still wouldn't do it by copying and pasting big hunks of text, either. Reasons for resorting to that range from wanting to be absolutely sure that things are being expressed correctly in ones third or fourth language, all the way to "Isn't that how it's supposed to be done?" The latter situation obtains in parts of Asia, where apparently there's an emphasis in some schools on verbatim transcription of authoritative sources. There's an interesting cite to Yu Hua's China in Ten Words, where one of those ten words is "copycat" (shanzhai):
As a product of China’s uneven development, the copycat phenomenon has as many negative implications as it has positive aspects. The moral bankruptcy and confusion of right and wrong in China today, for example, and vivid expression in copycatting. As the copycat concept has gained acceptance, plagiarism, piracy, burlesque, parody, slander, and other actions originally seen as vulgar or illegal have been given a reason to exist; and in social psychology and public opinion they have gradually acquired respectability. No wonder that “copycat” has become one of the words most commonly used in China today. All of this serves to demonstrate the truth of the old Chinese saying: “The soil decides the crop, and the vine shapes the gourd.”
Four years ago I saw a pirated edition of [my novel] Brothers for sale on the pedestrian bridge that crosses the street outside my apartment; it was lying there in a stack of other pirated books. When the vendor noticed me running my eyes over his stock, he handed me a copy of my novel, recommending it as a good read. A quick flip through and I could tell at once that it was pirated. “No, it’s not a pirated edition,” he corrected me earnestly. “It’s a copycat.”
This tendency isn't a good fit with a lot of things, but it especially doesn't work out so well with scientific publication. I haven't seen it stated in so many words, but a key assumption is that every scientific paper is supposed to be different. If you take the time to read a new paper, you should learn something new and you should see something that you haven't seen before. It might be trivial, it might well be useless, but it should be at least slightly different from any other paper you've read or could find.
Now, as the Retraction Watch comments mention, some of these plagiarism cases are examples of "templating", where original (or sort of original) work was done, but the presentation of it was borrowed from an existing paper. That's not as bad as faking up results completely, of course, but you still have to wonder about the value of your work if you can lift big swaths of someone else's paper to describe it. Even when the manuscript itself has been written fresh from the ground up, there's plenty of stuff out in the literature like this. Someone gets an interesting reaction with a biphenyl and a zinc catalyst, and before you know it, there are all these quickie communications where someone else says "Hey, we got that with a napthyl", or "Hey, we got that with a boron halide catalyst". Technically, yes, these are different, but we're in the land of least publishable units now, where the salami is sliced so thinly that you can read a newspaper through it.
So the authors regret this approach, do they? So does everyone else.