How Did "Muffin Top," "LOL" and "OMG" Get into the Oxford English Dictionary?

 "On Thursday, teenagers around the world discovered that they weren't, like, the first generation to use OMG. According to the Oxford English Dictionary, which listed the acronym among its newest crop of word additions, that distinction goes to British Navy Admiral John Arbuthnot Fisher. In 1917, Fisher wrote this sentence in a letter: 'I hear that a new order of Knighthood is on the tapis—O.M.G.(Oh! My God!)­—Shower it on the Admiralty!' He sent the letter to Winston Churchill.
Other additions this quarter include muffin top, which was first referenced as a baked good in 1914 and as the flesh roll that hangs over a waistband in 2003. The OED team has also admitted LOL, which first appeared in an electronic archive circa 1990, and a new sense for the word heart: 'to love' (as in 'I heart Slate'), which was first seen in print in a 1983 Associated Press article. (Some news outlets misreported that the ♥ symbol itself was being added to the OED.)"
So how did these words snag a spot in the famous dictionary?