Literacy. The way language is used in modern day.

Now I've heard that the way we use language in this generation is a lot different then how it was used 20 years ago. And I completely agree with that. But I've also heard that out generation (me being an 18 year old college student) that Literacy and the way language is used is "uneducated" or less in formal now a days. Now to a certain extent I agree with this, because of the way us teenagers use texting, email and use of slang. But I've heard that teachers and older adults say that they hear this use of informal language when in a serious situation. For example, I've had a college professor tell me when one of his students messaged him about his grade he used terms like "U" instead of "you" and "idk" which means "I don't know." Now personally I haven't heard of this form of language being used in situations like these until I started going to college. When I went to an interview for my first job when I was 16 I made sure I was using formal language because well, I know I had to. But I didn't even really had to think about using formal language because its kinda automatic in certain situations. And I thought this is how it was for most people. But apparently this is a much bigger problem then I thought it was. I would like to hear from other  and what they have to say about this subject. Just tell me any situation when you have heard this problem. If you have.