Develop a website for an international domain for easy localization into other languages in the future. I would like to know how search engines treat the sites where the language is dynamically determined (the language of the browser or, say, IP) and then stored in the Cookies. The user will be able to change the language of the site in his basement. A good example of such site - Vkontakte. I know that there are more educated ways to specify the language:
- To buy a domain, for example site.ru and site.de
- To make a subdomain, for example, ru.site.pw and de.site.pw
- Add language on all links, such as site.pw/EN/ site.pw/de/
But I heard that search engines determine the first two options as different sites, and the third option separee in implementation in the sense that all links have to specify the language using a function such as (best guesses):
<a href="/<?php current_language(); ?>/prices"></a>
But about the implementing method using Cookies, I'm asking about, I have nothing sensible could not naguglit. Share your opinions and experience please.