LOL

LOL or lol, an acronym for laugh(ing) out loud[1][2][3] or lots of laughs,[4][5][6] is a popular element of Internet slang. It was first used almost exclusively on Usenet, but has since become widespread in other forms of computer-mediated communication and even face-to-face communication. It is one of many initialisms for expressing bodily reactions, in particular laughter, as text, including initialisms for more emphatic expressions of laughter such as LMAO[7] (“laugh(ing) my ass off”) and ROFL[8][9][10] (or its older form ROTFL;[11][12] “roll(ing) on the floor laughing”). Other unrelated expansions include the now mostly obsolete “lots of luck” or “lots of love” used in letter-writing.[13]
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The list of acronyms “grows by the month”[9], 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.[14] These initialisms are controversial, and several authors[15][16][17][18] recommend against their use, either in general or in specific contexts such as business communications.

Laccetti (professor of humanities at Stevens Institute of Technology) and Molski, in their essay entitled The Lost Art of Writing, are critical of the terms, predicting reduced chances of employment for students who use such slang, stating that, “Unfortunately for these students, their bosses will not be ‘lol’ when they read a report that lacks proper punctuation and grammar, has numerous misspellings, various made-up words, and silly acronyms.”[15][16] Fondiller and Nerone in their style manual assert that “professional or business communication should never be careless or poorly constructed” whether one is writing an electronic mail message or an article for publication, and warn against the use of smileys and abbreviations, stating that they are “no more than e-mail slang and have no place in business communication”.

Source: https://en.wikipedia.org/wiki/LOL