This is not at all surprising. Other online dictionaries list both definitions as well, on the ground that a dictionary's purpose is to dispassionately report how people use words, not try to be consistent when people aren't consistent.
>Much to the chagrin of grammar-lovers everywhere, it turns out that this informal (and completely incorrect) use of "literally" has actually been added to three established dictionaries, as Reddit user andtheniansaid pointed out.
..."completely incorrect"...!
What is kind of useless is a word that can mean some thing or its opposite, and there is no way to tell from the context, eg:
"When the tiger went "Rawr! Rawrrr!", I literally fouled my breeches!"
Can't have a factual should. Shoulds are normative.
>What is kind of useless is a word that can mean some thing or its opposite
Is the word really useless or indeed useful if no one can provide a 'real' example of actual ambiguity between the two meanings? Furthermore, it's not as if ambiguity between one meaning and an opposite meaning is the greatest ambiguity there is-- if anything, it makes it particularly obvious which meaning the speaker intends.
Also, Wikipedia refers to two types of dictionary: prescriptive and descriptive. But even the descriptive type should provide information on how the word is used, eg: "sometimes incorrectly used to mean 'figuratively'".
Wait, think a minute. That description exactly corresponds with what I said. The "correct" usage of a word is precisely, exactly what the speaker thinks it means, at that moment in time.
If a dictionary listed a definition that was not in use by anyone, that would be different -- that would be incorrect.
> Also, Wikipedia refers to two types of dictionary: prescriptive and descriptive.
Yes, and there are no prescriptive dictionaries, at least not in English. The French have one, created by the Académie française:
http://en.wikipedia.org/wiki/Acad%C3%A9mie_fran%C3%A7aise
Apart from the French example, it seems telling people how to use words has fallen out of fashion, giving way to another example of evolution by natural selection.
So the person quoted doesn't actually know what a dictionary's purpose is. It seems there are still people who think a dictionary should prescribe, not describe.
This is by no means the only case where a word's meaning has changed over time, or even reversed its meaning. "Decimated", which now means destroyed or substantially destroyed depending on one's source, once meant reduced by a proportion of one tenth.
http://www.merriam-webster.com/dictionary/decimate
http://dictionary.reference.com/browse/decimate
Notice the difference in the listings between Merriam-Webster and dictionary.com. It's an old tradition with Merriam-Webster (and its predecessor Webster's Dictionary) to list the oldest definitions first. It seems newer dictionaries have reversed this practice. Speaking of reversals. :)