What is "all rights reserved" on the site?

Question

Copyright

I often saw on sites such an inscription "year * copyright sign * All rights reserved."
1) What are they writing for and how does it protect them?
2) Is such a thing documented for a specific site / company?
3) How to get it and what will happen if I don’t have one on my site, i.e. my site is not secure and can be copied?
3.1) How can you prove that the site is yours, from where it can be extracted to prove to others. Suppose it is located on my hosting and was uploaded earlier than a copy (if this happens) and without copyright, then the rights under the law are on me? - it's just not very clear how in this case it is fixed that I have the rights to the site. Without any documentation. (PS I'm the developer of the site.)

Answer 1

A copyright notice is required by the Geneva Copyright Convention (and some earlier ones, such as the Buenos Aires Convention ), without it, published material in countries that are party to the Geneva Convention alone may be used in the public domain.
However, at present, almost all countries protecting copyright, including Russia (since 1995) are parties to the Berne Convention , in which the principle of copyright presumption applies (it exists from the moment the work is created and does not depend on copyright marks, registration, etc. .), the legislation of the Russian Federation also complies with the Berne Convention, therefore, in practice, the copyright sign currently does not affect anything.
But, in the event of a withdrawal of any country from the Berne Convention, the provisions of the Geneva Convention will automatically apply in this country (under the terms of joining the Berne Convention), so the placement of a copyright mark can be considered insurance for the future.

Answer 2

The inscription reminds that the content is protected by copyright. The inscription does not carry a special legal burden, which means that the creators of the site are aware of the consequences of content theft and are ready to defend their case in court. Without this inscription, rights are protected in the same way. In short, this is a reminder.
Copyright may or may not be documented. This is why they don't get lost. Copywriters usually take action to make it easier to gather evidence that the content is theirs.
How to prepare an evidence base that "you are the first" - there are separate detailed articles. They won't fit in the answer.