Plagiarism is serious business. It's pretty odd when creative writers sink to that level, but from my own experience as an under and post grad writing student, you'd be shocked how many people, devoid of ideas, sink to that level.
So did Stephanie Meyer plagiarize passages from Breaking Dawn? Author Jordan Scott certainly thinks so, issuing a cease-and-desist letter after he noticed that her books share more than a passing resemblance to his novel, The Nocturne.
Sure, it's easy to accuse Scott of trying to jump all over Meyer long after she's become successful, for financial gain or to bump his own book sales. But this should certainly be looked into. After all, consider the case of Kaavya Viswanathan, the Harvard sophomore whose young adult novel, How Opal Mehta Got Kissed, Got Wild and Got A Life, triggered alarms for several of her fellow students, who were, well, shocked that someone they deemed mediocre so easily got a multi-book deal. A bit of research uncovered that she'd stolen entire passages and the plot points from a relatively unknown writer, Megan McCafferty. Viswanathan insisted she's merely 'absorbed' the author's style and writing. Verdict: stolen.
Being unfamiliar with both The Nocturne and Breaking Dawn, I'll have to wait and see what the evidence is against Meyer. Several people unsuccessfully sued J.K Rowlings following the epic success of the Harry Potter series for similar reasons. As many articles point out, the wording in vampire novels tends to be, well, cliche, so sometimes things sound the same, But how much is too much?