Ghostwriting for CEOs

Ghostwriting someone's blog seems to be stirring up some interesting discussions. I have a question for you. How is having a ghostwriter for a blog any different than a secretary cleaning up a boss's letters, emails, or other communications? As long as there have been businesses, secretaries have been fixing errors in letters and other communications. Some bosses would simple tell the secretary to pen a letter to a particular individual and leave the specific wording to his/her discretion; meanwhile, the boss would simply read the letter before signing and make any revisions at that time. Isn't ghostwriting a CEO's blog similar? If the CEO talks to the ghostwriter about potential topics, the ghostwriter has some direction and focus for the postings, making sure to run the copies by the CEO for any necessary revision and the final copy for approval. Smart, effective CEOs hire smart, effective administrative assistants, so why not hire a creative, well-spoken ghostwriter?