I am setting a Magento multilanguage website with subfolder as suggested by many seo and google guideline.

For example:

site.com/it (italian default)
site.com/en (english)
site.com/fr (french)
site.com/de (german)
site.com     (what to do with this?)

Magento makes it easy using "Add Store Code to URLs" showing correct language for each subfolder.

I read many threads about language subfolders but none of them is suggesting what to to with the root domain site.com.

My default language is /it, I may be wrong but it seems that magento keeps default language content both on site.com and site.com/it.

So what is best practice for when a user get to site.com?