Copyright is a type of property founded on a person's creative skill and labour. These properties can be songs, books, films etc. It gives you (and no one else) the right to publish, reproduce or perform the work among other things. If someone uses or copies the products you produced or sells them to other people, they break law and may be entitled for compensation.
Intellectual Property comprises patents and trademarks in addition to copyright. Copyright is different from patents and trademarks as you don’t need to register your product and pay a registration fee. If you make an invention you need to register it an pay to related authority.
Copyright is valid in the internet as well. You can’t download or share music or videos via internet as this will be violating law.
Downloading songs and other items without consent of owner is illegal. You can download items with permission of owner or buying from online store like iTunes. Downloading files without owner’s permission is illegal, even if you download them from overseas resources.
You can copy CDs, downloaded music files and videos for your private use if you already purchased them legally, you can’t share them with anybody else or you can’t copy them if they belong to someone else. Videos shouldn’t include TV broadcasts and shouldn’t be copied to another videotape.
Format shifting refers to the process of copying music into different formats. It is legal to format shift music, books, newspapers, magazines, video tapes, and photographs. However, it is illegal to format-shift computer games.
There are various legal actions for infringement of copyright. These include remedies, notices, fines and imprisonment.
In the US they have revised rules with copyrights which allow people to use other peoples work partially, as long as the person who created the material is attributed.