In the January 2007 edition of Harvard Business Review, there is a great article entitled: "How Leaders Create and Use Networks." What I found extremely insightful and highly applicable to sales was the Three Forms Of Networking:
1) Operational. where most contacts are internal (within your company) and specific to functions and skills required to getting the current job done.
2) Personal. here contacts are mostly external and oriented to current interests and potential future interests and also a wonderful source of references.
3) Strategic. here contacts are internal and external to your organisation often with experience and expertise very different to our own and orientated towards the future.
I see a huge level of applicability to sales. Let me explain by taking a quote from the article.
"What differentiates a leader from a manager, research tells us, is the ability to figure out where to go to enlist the people and groups necessary to get there." If we replace "leader" by great sales professional and "manager" by good sales professional, I think you will find that we have captured the single biggest difference between what separates good from great in sales today.
Success in sales tomorrow will be increasingly dependent on a) our ability to reinvent ourselves, ie. find new ways of defining our role in sales and b) developing new relationships, ie. networking. These two factors will enable us to deliver new levels of value to our customs.