Stan Carey writes about the usages and history of literally:
Last week I heard a news reporter on Irish television describe people as “literally gutted” by the news of job losses. She meant, of course, that they were devastated, not that their intestines were spilt: she used literally to intensify a figurative statement. This is typical of how the word is often informally used – many would say misused.
Like it or not, literally is used to mean more than just “literally”, and it has been for a very long time. Some people – I’m one of them – prefer to use it only in its narrower, more literal senses. A subset – I’m not one of these – insist on it. […]
Language is fundamentally metaphorical, and with literally we have walked a very long way from the Latin for letter. “[I]t’s impossible to tell where literality leaves off,” writes linguist Geoffrey Nunberg, “nor is there usually any practical reason for trying to do so.”
As an unapologetic fan of hyperbole, I make extensive use of the non-literal “literally”. I’ve never observed my usage causing confusion, so can fairly easily write off any such concern.
More generally, I’m not sure why some people insist on notions like “misuse”. I think it’s literally impossible to “misuse” a word, if the vitality of language arises from actual usage, rather than “correct” usage that some cabal imposes by fiat.
I should note that such a “cabal” is not literally a cabal, as they’re probably not politically motivated, and aren’t really very secretive about their existence or their priggishness. Similarly, this “fiat” cannot be understood as a literal fiat, because that would probably require the issuance of all sorts of very important and formal looking documents, or at least the use of one of those neat embosser things that notaries use for no discernible reason.