U ≠ YOU!

This is another instance where I would advise you to STOP doing this in text messages, emails, on social media, and any other forum where you think it's ok. If you are over the age of 16, this is especially not ok. If you're under 16, it's a bad habit to start. If you are 16-18, I attribute it to laziness and/or a short attention span. Yes, I have seen this in formal essays students have turned in for a grade, which makes me wonder if students surely know they shouldn't use this "abbreviation" in college essays or on job applications.

If you are an adult, write like one.

Do what you want when you're writing or sending text messages privately to friends and family, but when you write publicly, please be a good example to others.

If you don't have time to type or text the two additional letters required for the pronoun "you", perhaps now is not the best time to be sending a message at all.

I certainly realize this makes me sound old-fashioned. My problem is that the American English language was rotting well enough before this trend started. This habit did not begin because people didn't know what was correct usage. It began with a deliberate decision stemming from laziness.

"Hey! I don't have to go through the effort of thumb-typing Y-O-U! 'Cuz 'U' sounds just like "you," and therefore I can skip two letters! Oh my god, that is SO cool!"

This also reinforces the common ideas that "spelling doesn't matter" and "The important thing is to get my point across," which probably arose out of Whole Language instruction.  When I read sentences, text messages, posters, advertisements, etc. in which the letter U is supposed to represent the pronoun "you," I am not interested in the writer's "point" at all.

And just for the record, if you are over the age of 16...
  ur ≠ your or you're
  r ≠ our or are
  r u  ≠ are you

Please use our language with style and intelligence. Don't be the person who is used as the example for how NOT to communicate.