Is there anyone left, other than professional writers and editors, who knows the difference between "to" and "too"?
In the blogosphere, particularly in comments, "to" has become almost interchangeable with "too." When I first started noticing the error, I assumed it was just a typo, resulting from someone being in a hurry. But it has become far too -- yes, too -- common to be anything other than ignorance in most cases.
A dumbed down educational system and a post-literate popular culture mean that words are learned by hearing them, in speech or on TV, rather than reading them. So naturally the difference between homophones is incomprehensible.