Copy editing is important.
Word Nerd isn't getting political here, but check out this story that Vanity Fair did about Sarah Palin's resignation speech.
They assembled a top-notch team of editor/proofreader types to correct the speech for publication. Look up "proofreader marks" to decipher everything they fixed.
Word Nerd's not saying her pages look like this as she's revising, but it gives you the idea. Taken to the extreme.