Stackoverflow is really amazing. Last year when I joined the community was a little sceptical because there were already a lot of sites with similar content (although the concept wiki-forum is new to me) but it outpassed almost all (or just all) similar pages and the investment for the development in financial and technical sense probably wasn't as big as in some other business attempts which in the end fail inspite of great ideas behind.
Most of engineers focus on technology and look at the product from technical perspective. Recently I heard about some iPhone app (don't want to name it and offend anyone) which I would not invest a single minute for the development as I consider it useless and unethical but the guy who developed it made a fortune.
To make it short there are a lot of great ideas which fail and there are a lot of useless products which make big money (by the way don't get me wrong... I don't consider this site useless). Obviously there is a gap between the idea (or finished product) and selling and it would be really useful for engineers to achieve at least a bit of skills to promote their products.
I would be really thankful if anyone of you could suggest any good material to learn about business which would be useful to people who spend most of the time in research and development.