We are planning a website in 20 languages. Each page will have content in its language and link to origin article which will be on the main site in English. Is it better to have for each country www.us.domain.com, [www].es.domain.com, ... or www.domain. es, ...? I was thinking that if we link from all those pages on the same server from different domains to the same pages google can threat it as linking scheme and penalize it. Or not? But if we keep the same domain xy.domain.com there is no worry. But will for example Spanish local search engine index page es. domain.com or much quicker page domain.es? Thank you!
I think best strategy for international seo is. if you do have domainname.com, this will help your for targeting global market and if you have domainname.ca (canada), then you will get exposure in canada. you might like to read about internalnational seo. http://www.searchenginejournal.com/international-seo-need-your-help/14172/
For SEO purposes (for Google extra search results for example) I would recommend build all local sites within 1 domain, like you said for Greg Grothaus from Google said "if you use multiple domains, you loose extra search results with Google in case of multiple domains": however it is wise to buy local domain names if you have serious business and point them to local subdomains
...but subdomains ARE considered multiple domains... Your best bet, since these foreign language pages are only 1-page things and not separate websites, is to just make them folders off of the main extension (mysite.com/es, mysite.com/cn, etc) and set a "canonical tag" pointing back to the home page.