Sorry, but using examples of "WoW" and "u" in the same sentence is just silly.

Yes, if I had to type out World of Warcraft (or International Business Machines, or International House of Pancakes, etc) every time, I'd go nuts with my fingers being too tired to do anything. So I say "WoW", "IBM", and "IHOP" because those are standard, SELF-used acronyms. Notice the word acronym. It's a shortening of a name using the letters in the name.

"u" is simply the letters "y" and "o" left off of you because the letter u, when said in English, is the same as the word "you" said in English.

But we don't write like we speak. We don't type like we speak.

To summarize:
International Business Machines = 30 letters including spaces
IBM = 3 letters

you = 3 letters
u = 1 letter

Come on. Don't give me that because someone isn't a native speaker of English they get a free pass on the bullcrap that is "u" "ur" and those kinds of ascii poisoning.

Acronyms are NOT what we are talking about here.