Much of the work of any product designer is confidential- some projects more than others. Then there is the question of open-source, and when is the knowledge of the masses more beneficial that the knowledge of the few. While some open-source projects have been successful and profitable (which makes sense- it is the epitome of user-centered design), I enjoy a little old-fashioned confidentiality. As designers, its our bread-and-butter.
On a slightly different note, I had the good fortune to participate in a Boston IDSA portfolio review tonight. It was fun to go as a co-op because I was sort of in-between the professionals and the students. It was fun to hear the professionals feedback and see the students work (while offering a few comments/compliments of my own.) I was also blown away by the resources a locale can offer- tonight students had free access to 15 or so industry professionals giving free feedback on their portfolios... how great!