I don't blame computers. They don't write anything. I blame people, and I think the biggest reason is apathy. It is absolutely rampant in society today, and not just in writing. People just do not give a rip! Just about everything I buy or have done by someone is done incorrectly. Manufacturing quality is a perfect example. I admit to being a perfectionist, and overly critical of things, but it is beyond ridiculous today! Spelling? Grammar? What's that? There are no rules any more. The online version of Merriam Webster's dictionary includes every conceivable pronunciation of every word. They actually had a video clip on their website stating that if a certain pronunciation is commonly used, it is included regardless if it is considered improper by any authority. We are on the path to illiteracy folks, and "there ain't no stoppin' it."
