Is copyright in the site's footer usable at all?

Question

Most of the sites on Internet have copyright like:

site design / logo © 2012 stack exchange inc; user contributions licensed under cc-wiki with attribution required

I myself have not noticed it in ux.stackexchange.com until now that I needed it for my question. I don't think most of people see this part, so what is the purpose of it when most of us don't see that part.
We don't have copyright issues in our country, but again most of people in our country even do this? I think they just mimic these parts just to say their site is like a real site ;). Do I have to use copyright on the footer? Why?

P.S. my site is usable by all the people all around the world some with copyright laws some without it.

Answer 1

According to Wikipedia copyright is:

Generally, it is "the right to copy", but also gives the copyright holder the right to be credited for the work, to determine who may adapt the work to other forms, who may perform the work, who may financially benefit from it, and other related rights. It is an intellectual property form (like the patent, the trademark, and the trade secret) applicable to any expressible form of an idea or information that is substantive and discrete.

Therefore, if you think your work needs to be credited for, you can put the copyright symbol. If you have patent and you have published it in your site, then you need to apply copyright; to show the readers that you are responsible for the whole work. otherwise, if you think it is free to be adopted , changed without your permission, it need not be copyrighted! instead it can be Copyleft which fits your use case!

Answer 2

The usability of the copyright can be co-related to the fact that it sends a sense of authenticity to the users. If we don't see any such message, we tend to be suspicious. So, I can say over a time, our mental model has become like that and trust the site (one of the factors of many) when see copyright stuff

Answer 3

Placing the copyright notice in the footer:

• meets the legal need to have a copyright notice
• meets the users expectations about where a copyright notice is normally located
• keeps it away from the normal area of user interest (typically users scan in an 'F' shape)

Answer 4

Copyright notices in the site footer allow sites to clarify what sorts of rights management the owner is using. It is common on the internet for sites to use copyleft, creative commons, or other variant assertions of rights over content.

According to the Berne Convention and the various legal systems that adhere to it, it is not necessary to assert copyright to automatically be assigned it. This means it is reasonable to assume that the most restrictive version of copyright law applies where notice is not given. A copyright notice allows authors to assert different rights to the content that may be less restrictive.

As others have mentioned there are additional side cases - some users believe (usually incorrectly) that websites without a copyright notice are not protected. A copyright notice here allows sites to signal to these users that it is. In addition, copyright notices can add a positive trust effect, as they are usually symptomatic of larger organisations that care about content rights and users associate the notice with the sort of legalese that these organisations employ.