Copyright Criminals, which airs its documentaries on PBS, has an upcoming show on the rise of sampling in hip-hop music. While, the documentary focuses on copyright laws covering music it's not too difficult to apply lessons learned for other content including text found on web sites.
You may notice that I currently don't specify a copyright or Creative Commons license on my site. Where do I stand on the issue? I pretty much follow US Copyright laws which basically says using excerpts from an article is proper but it's illegal, outside of personal use, to copy a full article without permission. In the end though, it's not the law that I rely on but each persons own moral compass. That seems to work for me. It's only in rare cases that I've found people stealing entire articles without permission nor giving credit where credit is due.
Story found via Creative Commons