Instant messages and text messaging are encouraging lax writing skills all across age groups, but especially amongst teens and people in their 20’s who tend to use it more as a major form of communication. In part, this is because the entire point of both of these forms of communication is to post what you have to say and quickly as physically possible. Why spend several seconds “typing” something on your cell phone when one or two letters will get the point across? Then there is the “cool” quotient; knowing what these symbols and abbreviations mean makes you a part of the in crowd, however large that might be. It gives you a way to communicate with your friends without mom or dad being able to easily see what you’ve written. And when you’re using those media, it’s the way to write to your audience. There’s nothing wrong with that, so long as it stays in the realm in which it is useful, but try typing a cover letter for your resume with it!
The Internet in general is also contributing to a slide in the ability of people to write and spell well. In large part this is due to blogs and amateur sites which are poorly written and edited. With so many examples of bad grammar, mis-spellings, fragmentary sentences, and poor logic it is no wonder that people who spend a lot of time reading them begin to lose the ability to distinguish the good from the bad. It is easy to Google a subject and read about it for hours but it is far more difficult to find a source that would stand up to serious scrutiny for either writing ability or proper (and properly-credited) research. It’s all too simple for someone to copy the text from another site or to cobble together a series of ideas from several places without mentioning it. Seeing the rampant plagiarism may lead people to believe that this is the accepted way to communicate, rather than creating their own ideas and expressing the reasoning behind them. You can see many examples of this right here on Helium, although I hope that the ranking and flagging systems will lead to such articles being either dropped to the bottom or deleted entirely.
None of this is meant to say that there are no people under the age of 35 who can write a well-reasoned and grammatical communication. Of course, there are many. But these factors make it far more difficult to impress upon young people the need to learn grammar, vocabulary, logic, and how to use a library. And that, in turn, makes the jobs of their parents and teachers that much more difficult.