Sales and Strategy Forecast: If you have a target to achieve you can plan out your work according. It's just like keep the figures real and amenable. Unrealistic figures would not help you ever to get the target on time. Secondly with these forecast, you can compare your marketing strategies and come up with the best solutions for future activities.
Customer Segment _ this is talked about most of the time, but let's accept the fact that today's customers are fragmented to smaller niches. Your product and service will not be consumed by only one segment and at critical mass. it is likely to be consumed by smaller segment and multi. No more critical mass, but rather a solid spread of niches. For example, who buys iPod's today? If Apple only think about yuppies they are making a big mistake because apparently iPod is also used by women and people with active lifestyle. Another example, who buys from hypermarket? If hypermarket only focuses on households they may not survive or be successful like today. Hypermarket main segment is actually small business restaurant operators that buy in larger quantity compare to households and on daily basis. I've been there, I know! LOL