“Marketing staffers sometimes try to have salespeople help them profile customers. ‘After all,’ they think, ‘the salespeople know their customers better than anyone else, so why shouldn’t they fill in their demographics or firmographics?'” notes Bill Singleton, president of Algonquin, IL-based database marketing consultancy Singleton Marketing. But they forget that no one can serve two masters at the same time. Salespeople are paid for selling, not demographic profiling, just as marketing staffers are paid for planning, promoting and tracking but not for pushing products.