Sharing knowledge in technology industries
I'm a videogame developer, programmer to be more specific, I have often been faced with problems within a company, that someone, somewhere in that same company had sometime been faced with and solved it.
Sometimes this person had left the company, others he was busy, others he was just unwilling to share the knowledge.
A friend of mine once decided to make a presentation at a public conference about a particularly hard problem he had to solve, how he solved it and other alternatives. When his company found out about this presentation they forbid him to do it out of mere fear that their "secrets" would be revealed, secrets that when my friend resigned took with him since the company did not know anything.
I believe these secrecies and competitivity can't help anyone really, not the individual, not the companies and not the industry as a whole, and I would like to make a presentation on this matter on the next annual game dev conference (not the GDC, but our humble little version of it here in argentina :$ ).
What points should I focus on? how have others, even from different industries faced this issue? What are the legal implications and to which point should we let them limit our potential? Why aren't most companies schooling their employees to make them better? What arguments do they have against these practices if any?