Could this finally spell the end for Motorola's well-worn FOUR LETR marketing campaign? Hard to say -- Chief Marketing Officer Casey Keller didn't invent it to begin with -- but for what it's worth, he's gone. It seems Keller left under the cover of night last Friday, while Motorola put off announcing his departure until Thursday of this week; whether that's an indication that he left of his own volition or was shown the door, we don't really know. Interestingly, the company says that it won't be replacing him, instead moving his responsibilities down to his underlings in the B2B and mobile divisions. Knowing what we know of executive compensation packages, that's got to save a buck or two.