Your product managers, sales people and your.
Finally, the census bureau is a great repository of free demographic and regional data.. Your product managers, sales people and your customer support personnel (if you have them) are also terrific sources of info, as are the public reports of industry analysts, from sales and marketing studies and market analysts’ reports (like Charlene Li’s).
Original text search at: ypnblog.com/blog/2006/10/page/2/