I stumbled into fiction writing without much background, and thus had a lot to learn. One of those things was use of brand names, quoting song lyrics, and the like.
I was working on my first long work of fiction, and passed it by my writing partner.
"You might want to remove the mention of Kleenex, by the way," she said. "It's a trademark, and you could get into trouble."
"But all my main character does is blow his nose," I protested.
"Sure, but why take a chance? In my opinion, he could just as well use a generic tissue."
Would I have gotten into trouble? Most likely not, as I didn't say anything negative about the Kleenex that could have resulted in loss of sales.
Names and titles can't be copyrighted, but brands can be trademarked, and trademarks are also protected by fair use. Copyright and fair use is a complicated subject, and any particular use requires careful analysis. Fair use is judged relative to four factors: purpose and character of the use, the nature of the material being quotes, the amount used, and the effect on the market. Small amounts of material and non-commercial use are less likely to be challenged.
So a mere mention of a product, song, or other trademarked or copyrighted material is most likely okay, but if my character chokes on Spaghetti-Os and dies, I might want to switch to a home-made meatball. Mentioning the name of a song would, again, most likely be all right, but quoting the lyrics without obtaining permission could get me in legal hot water.
What is fair game? Works in the public domain, titles and short phrases, facts, theories, ideas. US Government work. Anything published in the United States before 1923 is in the public domain. Anything where the copyright has expired or wasn't registered properly.
Kleenex is a trademark, which is why my writing partner pointed it
out. If you have any doubt as to whether something is protected, the Patent and Trademark Office website will allow you to search for copyrights and trademarks. The public domain music site will turn up many more recent tunes in the public domain.
If you're a writer, be aware and take care.
Margaret Fieland is one of the poetic muselings. Their anthology, Lifelines, was published in Nov, 2011. You can find her on the web at http://www.margaretfieland.com/ or at http://poetic-muselings.net/