From an interview with Steven Pinker:
Having once been a young person myself, I remember the vilification that was hurled at us baby boomers by the older generation. This reminds me that it is a failing of human nature to detest anything that young people do just because older people are not used to it or have trouble learning it. So I am wary of the “young people suck” school of social criticism. I have no patience for the idea that because texting and tweeting force one to be brief, we’re going to lose the ability to express ourselves in full sentences and paragraphs. This simply misunderstands the way that human language works.
All of us command a variety of registers and speech styles, which we narrowcast to different forums. We speak differently to our loved ones than we do when we are lecturing, and still differently when we are approaching a stranger. And so, too, we have a style that is appropriate for texting and instant messaging that does not necessarily infect the way we communicate in other forums. In the heyday of telegraphy, when people paid by the word, they left out the prepositions and articles. It didn’t mean that the English language lost its prepositions and articles; it just meant that people used them in some media and not in others. And likewise, the prevalence of texting and tweeting does not mean that people magically lose the ability to communicate in every other conceivable way.