The Economist offers an overview:
A neologism or new sense of a word catches on, unlike the many neologisms that didn't, and lexicographers ratify what everyone else already knew: that lots of people were saying "occupy" this year, or that in Britain, the "squeezed middle" was the top political catchphrase of 2011. Merriam-Webster, being a dictionary maker, picked a word that many people looked up on its website, and so went with "pragmatic" instead of "occupy". Nonetheless, "occupy" is the frontrunner to win the Oscar of WOTYs, that given by the American Dialect Society.
Geoffrey K. Pullum levies his complaints against "squeezed middle," routinely used by the UK Labour Party:
[M]y real objection is not to the feebleness and blatantly political origin of this phrase (which ordinary people are simply not using), but to the fact that it is fully compositional: squeezed just means "squeezed", and middle just means "middle", and if you put the two together you have the literal meaning. It is ridiculous to think of putting this in a dictionary — as opposed to a collection of political phraseology and cliché.
Ben Zimmer counters Pullum at length.
The Dish 