LOL, and other TLA’s

People use ‘LOL’ (Laughing Out Loud) a lot. It’s become one of the most used TLA’s (Three Letter Acronym) that I know of. Are they really laughing out loud, and do people around them wonder when they break into a round of laughter for no apparent reason? Or has lol gone from meaning, “laughing out loud” to “I have nothing else to say”.