All rights reserved

In the past, the phrase was required as a result of the Buenos Aires Convention of 1910 which mandated that some statement of reservation of rights be made in order to secure protection in signatory countries of the convention. It was required to add the phrase as a written notice that all rights granted under existing copyright law (such as the right to publish a work within a specific area) were retained by the copyright holder and that legal action might be taken against infringement.
Since copyright law is neither straightforward nor widely understood in its details – nor is the Buenos Aires Convention's previous requirement, and the current deprecation of the phrase, common or lay knowledge, it continues to hold popular currency and serve as a notionally-useful convention widely used by artists, writers, directors, photographers, designers, and other content-creators with the intention that it should function as both sign and warning that the content alongside which it appears cannot be copied freely. It is unclear, however, if the phrase has any legal effect in any jurisdiction. In spite of this, its popular use continues. Provided by Wikipedia
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