Abbreviations and acronyms were invented long before text messaging, but serve the same broad purpose: to speed up communications. Who (with the exception of students trying to fill minimum-word-count essay quotas) wants to write out "North Atlantic Treaty Organization" eighteen times in the course of a document? Who would rather read it eighteen times when the four-letter, two-syllable "NATO" is available?
One small problem. "NATO" can also stand for "No Action, Talk Only"; "Night At The Opera"; "Not Another Teen Organization"; "National Association of Timeshare Owners"; "National Association of Taxicab Owners"; or some 50 additional possibilities. The slightest ambiguity of context can leave a sizable percentage of readers--especially those to whom an alternative meaning is the "normal" one--scratching their heads.
The proven method for maximizing both understanding and efficiency is to spell out the phrase the first time--"North Atlantic Treaty Organization (NATO)"--and use the now-clearly-defined acronym thereafter. But as with jargon, many writers never consider that their everyday language may be someone else's first-time encounter. Unless you're dealing with an acronym that has achieved common-noun status (such as "radar" for "RAdio Detection And Ranging"), follow the advice from the classic The Elements of Style: "Even if everyone did [know the meaning of any given acronym], there are babies being born every minute who will someday encounter the name for the first time. They deserve to see the words, not simply the initials.... Many shortcuts are self-defeating; they waste the reader's time instead of conserving it."
And especially these days, wasting someone's time is the unforgivable sin.
See also Acronym Finder.