LOL (also written with some or all letters lowercase, most commonly as lol or LoL) is a common element of Internet slang used historically on Usenet but now widespread in other forms of computer-mediated communication, and even face-to-face communication. It is an abbreviation for "laughing out loud" or "laugh out loud". LOL is one of many initialisms for expressing bodily reactions, in particular laughter, as text, including initialisms such as ROTFL ("roll(ing) on the floor laughing"), a more emphatic expressions of laughter, and BWL ("bursting with laughter"), above which there is "no greater compliment" according to technology columnist Larry Magid. Other unrelated expansions include the less common "lots of luck" or "lots of love".
The list of acronyms "grows by the month" and they are collected along with emoticons and smileys into folk dictionaries that are circulated informally amongst users of Usenet, IRC, and other forms of (textual) computer-mediated communication. These initialisms are controversial, and several authors recommend against their use, either in general or in specific contexts such as business communications.
Yunker and Barry in a study of online courses and how they can be improved through podcasting have found that these acronyms, and emoticons as well, are "often misunderstood" by students and are "difficult to decipher" unless their meanings are explained in advance. They single out the example of "ROFL" as not obviously being the abbreviation of "rolling on the floor laughing" (emphasis added). Haig singles out LOL as one of the three most popular initialisms in Internet slang, alongside BFN ("bye for now") and IMHO ("in my humble opinion"). He describes these acronyms, and the various initialisms of Internet slang in general, as convenient, but warns that "as ever more obscure acronyms emerge they can also be rather confusing". Bidgoli likewise states that these initialisms "save keystrokes for the sender but [...] might make comprehension of the message more difficult for the receiver" and that "[s]lang may hold different meanings and lead to misunderstandings especially in international settings"; he advises that they be used "only when you are sure that the other person knows the meaning".
Hueng, in discussing these acronyms in the context of performative utterances, points out the difference between telling someone that one is laughing out loud and actually laughing out loud: "The latter response is a straightforward action. The former is a self-reflexive representation of an action: I not only do something but also show you that I am doing it. Or indeed, I may not actually laugh out loud but may use the locution 'LOL' to communicate my appreciation of your attempt at humor."
David Crystal notes that use of LOL is not necessarily genuine, just as the use of smiley faces or grins is not necessarily genuine, posing the rhetorical question "How many people are actually 'laughing out loud' when they send LOL?". Franzini concurs, stating that there is as yet no research that has determined the percentage of people who are actually laughing out loud when they write "LOL".
Victoria Clarke, in her analysis of telnet talkers, states that capitalization is important when people write "LOL", and that "a user who types LOL may well be laughing louder than one who types lol", and opines that "these standard expressions of laughter are losing force through overuse". Egan describes LOL, ROTFL, and other initialisms as helpful as long as they are not overused. He recommends against their use in business correspondence because the recipient may not be aware of their meanings, and because in general neither they nor emoticons are (in his view) appropriate in such correspondence. Lindsell-Roberts shares that view and gives the same advice of not using them in business correspondence, "or you won't be LOL".
Geoffrey K. Pullum points out that even if interjections such as LOL and ROTFL were to become very common in spoken English, their "total effect on language" would be "utterly trivial".
Conversely, a 2003 study of college students by Naomi Baron found that the use of these initialisms in computer-mediated communication, specifically in instant messaging, was actually lower than to be expected. The students "used few abbreviations, acronyms, and emoticons". The spelling was "reasonably good" and contractions were "not ubiquitous". Out of 2,185 transmissions, there were 90 initialisms in total, only 31 CMC-style abbreviations, 49 emoticons, and just 76 occurrences of LOL.
Most of these variants are usually found in lowercase.
In Welsh, lol means nonsense - e.g., if a person wanted to say "utter nonsense" in Welsh, they would say "rwtsh lol".