http://www.slate.com/id/2202262/

From the article:

“Most Internet memes have the lifespan of fruit flies. But there’s evidence to suggest fail is here to stay. For one thing, it’s easier to say than failure. (Need for brevity might explain why, in Webspeak, the opposite of fail is not success but win.) And there’s a proud tradition in English of chopping off the endings of words for convenience. Between Old and Middle English, many nouns stopped being declined, says Anatoly Liberman, an etymologist at the University of Minnesota. Likewise, while Romance languages still conjugate their verbs, English keeps it relatively simple: I speak, you speak, we speak, etc. It’s also common for verbs to become nouns, Liberman points out. You can lock a door, but it also has a lock. You can bike, but you can also own a bike. There was great fuss a century ago among readers of the British magazine Notes and Queries when it used the word meet to refer to a sporting event. It’s not surprising that failure would eventually spawn fail.”