Google's John Mueller has published a good article on working with multi-regional web sites. He confirms that country-code Top Level Domains (ccTLDs) are the best way to host multi-regional content. He also clears up some of the myths surrounding duplicate content on multi-regional domains, which is most welcome.
John doesn't mention that the same thinking applies even if you are targeting a single country. A ccTLD is the best way to indicate the location of your target market to search engines - and to that market itself, of course.
A URL gives you at least five places to target a country: domain (ccTLD), subdomain (de.domain.com), directory(www.domain.com/de/), path parameters (www.domain.com/;domain=de) and query parameters(www.domain.com/?domain=de). However, there are lots more axes for the content to be split along:
- Category - Web, Enterprise, Social, Real Time
- Context - Intranet, Library, Personal
- Topic - Health, Travel, Jobs, etc.
- Vertical - Finance, Education, Government, etc.
- Platform - Desktop, Mobile, Television, Kiosk
- Format - Text, Image, Audio, Video, Map
(Note: the above is slightly modified from a table provided by Search Patterns, an excellent read)
Given this number of ways of organising content, and the fact that the location and language of your target audience are major considerations (worthy of a major axis), in all but the most trivial cases a ccTLD is the obvious choice for geo-targeting. It's good to see official written confirmation of this from Google.