There was a great article around a year ago about how the Obama White House handled letters to the president. Obama wanted to personally read and respond to about 10 per day (IIRC), but his response was in the form of jotting down thoughts and notes as he read the letter and handing them off to letter writers who knew the president’s speaking and writing styles well enough to write “his” response. I doubt the average CEO has dedicated letter writing staff, but those who are more serious about responding to customers probably have assistants doing something similar.