If you’ve different top-level Domains, e.g yourdomain.com, yourdomain.co.hk, yourdomain.com.au, yourdomain.com.hk, you may post similar contents to these websites.

For example, you may post company news or some announcement on the web page of different domains. Is it a kind of content duplication? How Google treat this kind of content duplication?

Google Webmaster Help answer this question in Youtube. It’s ok to post similar content on different TLDs as it is different from what Spammers did on content duplication. Spammers will try grep hundreds or thousands cheap domain to post similar content. But for company website, they normally may have few TLDs for different countries.