It turns out that Hornstine had been writing regular columns for the Camden Courier-Post, like this one on Thanksgiving, except she had a little trouble with the whole Don't Steal Other People's Words Without Giving Them Credit idea, which, apparently, was one of those things only taught at her high school itself, and not by her tutors. So Hornstine borrowed liberally from Supreme Court justices Potter Stewart and William Brennan, President Clinton and others without attribution -- without quotation marks, even.
Here's a run-down of some of her plagiarism offenses, and here's her apology, in which she claims:
Recently, I was advised by the editors of the Courier-Post that I had not properly cited work for articles that I submitted. These voluntary articles were not written for class assignments. I kept notes on what I had read. When finalizing my thoughts, I, like most every teenager who has use of a computer, cut and pasted my ideas together. I erroneously thought the way I had submitted the articles was appropriate. I now realize that I was mistaken. I was incorrect in also thinking that news articles didn't require as strict citation scrutiny as most school assignments because there was no place for footnotes or end notes.
I am not a professional journalist. I was a 17-year-old with no experience in writing newspaper articles. Upon reflection, I am now cognizant that proper citation allows scholars of the future to constantly reevaluate and reexamine academic works.
Hornstine will be attending Harvard in the fall, where she had better memorize the following passage from Harvard's Student Handbook":
Preparation of Papers and Other Work: Plagiarism and Collaboration
All homework assignments, projects, lab reports, papers and examinations submitted to a course are expected to be the student's own work. Students should always take great care to distinguish their own ideas and knowledge from information derived from sources. The term "sources" includes not only published primary and secondary material, but also information and opinions gained directly from other people.
The responsibility for learning the proper forms of citation lies with the individual student. Quotations must be placed properly within quotation marks and must be cited fully. In addition, all paraphrased material must be acknowledged completely. Whenever ideas or facts are derived from a student's reading and research or from a student's own writings, the sources must be indicated.
edited to add: If I'm going to be talking about proper attribution policy, I'd better note that I learned of this story via Romenesko.