Craig’s List? Then – boom – it was a global phenomenon.
So is there a copyright and if so, who owns it? Under copyright law, the author of the work (the Craigslist ad) claims copyright. But that presumes the posting is a copyrightable work and it's not always clear if that's true. We think the determination depends on the ad's length and the unique language used in the ad. As a general rule short phrases, or “stock” advertising terms are not protected under copyright. And under a principle known as the merger doctrine (or idea/expression doctrine), a want-ad writer can’t claim copyright if the ways to express an ad are limited -- say “Roommate Wanted: No Meat Eaters, Please.” Even if a want-ad can be protected under copyright, the reproduction in a book might be excused as a fair use (or as a de minimis, or “trivial” use of the material).
Conclusion Dept. As general rule, if you are simply quoting a few Craigslist ads in a personal narrative – and particularly if you are using those excerpts for purposes of commentary or criticism -- you can probably exercise your rights under fair use.
The music thing. Because you didn’t ask, we'll sidestep your comments about reproducing four lines from a pop song. But if we were a betting blog, we’d bet that most such uses in a personal narrative would be excused as a fair use.