Google launched its Link Disavow tool today. If you haven't read about it yet, you can do so here.
There are a few things Google mentions about it at the end of a blog post, I think are worth highlighting, with regards to international domains, subdomains and www vs. non-www.
Google ends its announcement with a Q&A section, and the last few are about these items. Here is what Google says:
Q: Do I need to disavow links from example.com and example.co.uk if they're the same company?
A: Yes. If you want to disavow links from multiple domains, you'll need to add an entry for each domain.
Q: What about www.example.com vs. example.com (without the "www")?
A: Technically these are different URLs. The disavow links feature tries to be granular. If content that you want to disavow occurs on multiple URLs on a site, you should disavow each URL that has the link that you want to disavow. You can always disavow an entire domain, of course.
Q: Can I disavow something.example.com to ignore only links from that subdomain?
A: For the most part, yes. For most well-known freehosts (e.g. wordpress.com, blogspot.com, tumblr.com, and many others), disavowing "domain:something.example.com" will disavow links only from that subdomain. If a freehost is very new or rare, we may interpret this as a request to disavow all links from the entire domain. But if you list a subdomain, most of the time we will be able to ignore links only from that subdomain.
To disavow an entire domain, you'll want to use a format like: domain:www.example.com.