Copyright protects many different phenomena: texts, computer programs, music, theatre, movies, photographies, visual arts, architecture, applied art and works that have been expressed in other ways. There are also a number of related rights, such as those for artists, companies in the recording, broadcasting and movie industries, photographers and database producers.
For example, for a song to be considered a work, it must be sufficiently original. That assessment is difficult and disputes may in the end be settled by courts. A simple general rule is that if it is unlikely that two persons would create, for example, a text identically or similarly, the text is probably sufficiently original to qualify as a protected work. Note that only the form of the text is protected, not the ideas as such, or concepts. Often, the requirements for copyright protection are considered to be relatively low.