Facebook wanted to figure out how its users signified laughter, and it found that more than half of them favored a simple haha or one of its many variants (hahahahahaha, for instance). About one-third loved a good emoji, while 13.1 percent used hehe. Perhaps somewhat surprisingly, lol—an abbreviation for “laugh out loud”—was used by 1.9 percent of users.
While the acronym has fallen out of favor on Facebook, its use and meaning actually have expanded. According to John McWhorter, LOL signals empathy these days more than chuckles. “What began as signifying laughter morphed into easing tension and creating a sense of equality,” he wrote for CNN. “That is, LOL no longer means anything. Rather, it does something—conveying an attitude.” (Slate)