However, social media do help spread tastes when it comes to movies and music, she added.
It's also possible that people tweeting about dangerous behavior are lying, Indiana University anthropologist Ilana Gershon said. Some users create Twitter personas as a sort of experiment, she added.
"It's not just the act of doing it, it's the act of announcing it publically," Gershon said. "For some people, it's really fun to lie about risky behavior. They get to see what a certain kind of response would mean without actually doing it."
Gershon wrote a book about how Facebook affects relationships. She is now researching how people create personas on Twitter tailored to landing certain jobs.
"People constantly believe other people's profiles, and admitted to me a great deal to which they lie on their own," she said.
Canadian pop artist Drake coined the acronym in a song called "The Motto." YOLO's popularity online began in California last October before spreading to Florida and Texas, up the East Coast and then to the rest of the country, according to Google Trends, which maps search term popularity over time.
According to Topsy, other YOLO Twitter trends included dialing a random telephone number and wearing or not wearing knee pads.
Eventually, Twitter users started reminding the YOLO crowd that they didn't have horcruxes, the soul fragments that Voldemort thought would make him immortal in the Harry Potter series. About 304,000 tweets contained both the terms YOLO and horcruxes.
Think you know the most popular health search trend of 2012? Think again. Read our story.