Domain Filtering automatically segregates websites from different countries into their respective regional editions. This segregation is done on the basis of domain names. For instance a website from Australia would generally have a domain .au. The Domain filtering mechanism looks at the domains of all websites and creates a country specific edition listing.
Some Search Engines also have region specific editions which contain listings from the whole of that region. As an example: A French edition of Google may also return German or Spanish websites in some cases.
Domain Filtering has a drawback though. This mechanism can only filter out websites based on the domain name, and hence .com is always considered to be a United States website. This is obviously not true. Many websites from other countries also have .com domains.

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