Disclaimer: I own nothing; it all belongs to J.K.Rowling. I'm just borrowing the characters to play with for a while. This is for pleasure only, no profit is being made, and no copyright infringement is intended.
That's the disclaimer from a story I recently finished, The Seventh Horcrux by Melindaleo. (And let me say upfront that I think Melindaleo is a good writer whose fics I have enjoyed. She's just the author whose work I happened to be reading when this got stuck in my craw, so she's the one getting picked on here.) For those of you who aren't familiar with fic-writing lingo, the disclaimer is just a brief acknowledgement on the part of the author that he or she has no legal right to use the characters and associated concepts being written about. Most fanfic authors are pretty breezy about it, and write disclaimers similar to the one I quoted above. Which is unfortunate, because they're somewhat nonsensical.
Take the first sentence. Melinda doesn't own nothing; she owns the story she wrote. She may not have come up with the characters or with horcruxes, but she did come up with the story and the words with which she told it, and that story and those words are hers just like Rowling's are Rowling's. In fact, Rowling has said that one of the reasons she has always avoided Harry Potter fanfic is because she doesn't want to be accused of having used an idea that a fanfic writer came up with. Dan Harmon and the Community writers have said the same. Part of that is professional pride, I'm sure -- what author wants to be accused of stealing someone else's idea? -- but I'm sure that avoiding legal liability is part of it too. As the "My Sweet Lord" case demonstrated, you can be held liable for even subconscious plagiarism.
The last sentence is pretty ridiculous too. "No copyright infringement is intended?" What's that suppose to mean, that she sat down to write a letter to her grandmother but accidentally wrote a Harry Potter fanfic? Of course she intended to violate the copyright, just like I did when I wrote all my fics. (Also, I might add, when I created the icon attached to this fic, which actually violates two copyrights.) And even if it was somehow magically unintentional, see the last sentence of the previous paragraph.
Another problem I frequently see with disclaimers is misattribution of credit. A lot of Community fic writers say that Community is owned by Dan Harmon. Except, no, it's not; the Harmonless fourth season is proof enough of that. Likewise, Joss Whedon doesn't own Buffy the Vampire Slayer, despite the claims of almost every Buffy fic writer in the world. Melindaleo was guilty of this one too, a little bit. In another fic, she titled one of her chapters "Homeward Bound," and in that chapter's disclaimer she wrote, "the chapter title belongs to Simon and Garfunkel," but in fact Paul Simon, the songwriter, is the sole copyright claimant. (Also, there was need to disclaim it in the first place. Copyright law does not protect names, titles, or short phrases or expressions. It was a nice gesture though, and personally I enjoy knowing why an author chose to do something in a particular way.) The most memorable example of this latter sort of misattribution is an fic I read a long time ago that quoted a song from the Fox Animation Studios movie Anastasia, and said in the disclaimer that the lyrics were property of Disney.
My disclaimers tend to be very straightforward: a simple statement of who owns the copyright, e.g. "Community and the related characters are © Sony Pictures Television Inc. and and Open 4 Business Productions LLC." For that Superman/Community fic I posted the other day, I even went to the trouble to visiting the DC Comics website to make sure I attributed Superman correctly. That said, I'm not always good about crediting copyright holders when I post poems or works of art or other such things here in my journal. Sometimes I remember, sometime I don't. I should make that a resolution for 2014: be more thoughtful about credit other people's work.
Also, I probably should cite the creators in my fic disclaimers, even if they're not the copyright holders. DC Comics names Jerry Siegel and Joe Shuster as the creators of Superman in every Superman comic they publish, and every episode of Community names Dan Harmon as the show's creator in the opening credits, even on the fourth season episodes he had nothing to do with. Of course, those credits are contractually obligated, and since I'm not a signatory to those contracts I'm not obligated to do squat, but it seems like the right thing to do.