In his essay “10 Big Myths about copyright explained“, Brad Templeton writes:
[…] almost all major nations follow the Berne copyright convention. For example, in the USA, almost everything created privately and originally after April 1, 1989 is copyrighted and protected whether it has a notice or not. The default you should assume for other people’s works is that they are copyrighted and may not be copied unless you know otherwise.
Read the whole page: copyright myths – read me