You can't violate copyright by telling someone what you know
in reply to Re^3: Code Samples and Previous Employers
in thread Code Samples and Previous Employers
Yes, technically you can, depending on where in the world you live, and what you do. For example, under Canadian copyright law, you can only read a "reasonable portion" of a book out loud: even though reading out loud doesn't make a copy, and certain tells someone what you know about the book. If you completely re-word each passage, you may or may not be okay. After all, translations into another language usually change almost every word of the original text, but they are still legally considered "derivative works".
In short, copyright law here is nasty, confusing, and horribly nebulous: the courts decide almost everything, like what a "reasonable portion" is, or whether your new version consists of a "significant part" of the original. You'll stay on the right side of the law only if you memorize a lot of case law, have a very good IP lawyer, and/or carefully guess how the judge will rule. Unfortunately, the Copyright Act itself is just a very crude jumping off point; the actual law is inside the minds of the judges who enforce it.