Is it a coincidence that Miley's VMA performance coincided with Oxford Dictionary Online's addition of "twerk" to its collection? It seems that dictionaries are trying to make themselves relevent in an online world, but I wonder what new additions like "twerk," "phablet," and "srsly" are really contributing.
The Atlantic recently looked into the words that were added to the dictionary in the '90s. For every "geek" and "icon", there is an obsolete "mouse potato" and "infobahn." The dictionary did not help preserve the latter words; they are now only funny memories of a past that was squinting into a technology-filled future.
What distinguishes a traditional dictionary from more colloquial internet references, such as Urban Dictionary? It has traditionally been a matter of authority–the dictionary knows about real English. It knows less about slang and acronyms. Of course, certain slang does withstand the test of time, but I don't think twerk has proven itself yet. And the dictionary's choices seem arbitrary. It may now have "TL;DR" and "derp," but it doesn't have "upvote" and "LMFAO." It's not the dictionary's job to be hip, and it makes it seem even stuffier when it tries to be.