"We're going to see Iran, in my opinion, move back in [to Iraq] at literally the speed of light."This line attracted a fair amount of ridicule on Twitter and the blogosphere for, of course, misusing the word "literally." It would be very difficult for Iran to send troops into Iraq that are traveling 300 million meters per second.
This use of "literally"—as an intensifier, much like you would use "absolutely" or "extremely"—is becoming more and more common. Vice President Joe Biden is a fan; The Fix blogger Chris Cillizza was also a recent transgressor. There's now a blog devoted to its particularly humorous misusages. Primarily, though, you'll hear it in conversation, especially (in my experience) among young people (compare to "like, totally"). The frequency of this misapplication seems like it has spiked in the past five years or so, and it gives traditionalist grammarians fits.
The problem is—as with many linguists' favorite misusages to gripe about—"literally" is not the latest example of how the internet age is deteriorating our language; it has been misused in this way for at least 200 years. In 1769, Frances Brooke wrote in The History of Emily Montague, "He is a fortunate man to be introduced to such a party of fine women at his arrival; it is literally to feed among the lilies." The famous Mark Twain was also an offender in Tom Sawyer: "And when the middle of the afternoon came, from being a poor poverty-stricken boy in the morning, Tom was literally rolling in wealth." Rick Perry's comment from last night was only the latest example of this fine literary tradition. Moreover, of course, Perry was merely employing a speech pattern that most of us have slipped into in the past—myself included. Considering that usage drives grammar, it's not a stretch to say that "virtually" or "utterly" has become one of "literally's" accepted definitions. Here in the year 2012, I don't think it's fair to condemn Perry for jumping on the bandwagon.
That said, I do wish "literally" were used with more care, for the sole reason that, once it is (mis)appropriated for that purpose, there will be no word left to mean "literally"! If you think about it, the words "really," "truly," and "actually" underwent similar transformations; if someone is "actually about to die laughing," that is not meant in the "actual" sense. Yet we hear this just as often as "literally," and it's probably more accepted—because we always had "literally" to fall back on when we meant that someone was literally dying from laughing too hard. Now there is no universally agreed-upon word to denote this; we will probably end up continuing to use "literally," which could create some unfortunate confusion considering its two possible (and practically opposite) meanings.
So here's your daily Baseballot public service announcement: the next time you're tempted to use the word "literally," think twice about whether you literally mean "literally." It could be the difference between life or death.