I love Project Gutenberg and similar sites for making public domain ebooks available to everyone for free. But yesterday, I learned that those texts might come from abridged editions. And there is no way to know unless you're familiar with the original. Or if you just happen to run into the difference while having coffee and lunch at a lovely bakery.
Yesterday, I was reading the Oxford World's Classics edition of "East Lynne" by Ellen Wood, and I wanted to post a quote online to talk about it. So I went to the Project Gutenberg copy of the book to grab that quote. But the digital text was missing most of the quote! It was missing three sentences about the character Mr. Dill (about 70 words or more in total). Also, my Oxford World Classics edition doesn't include periods after "Mr" and several terms (which is supposed to be the British style), but this abridged edition added periods.
I have three old copies of East Lynne. And one was obviously abridged. The size difference is obvious. The nicest one is 596 pages, and it includes the missing text. One is 252 pages -- and the same three sentences are missing.
So when someone mentions that they paid for a Penguin Classics edition or an Oxford World's Classics edition, don't assume that they are dunderheads who don't know that they can get free copies from sites like PG. They might want a more academic edition that compares to the original text. And they might want something with footnotes.