Matt Cutts, Google's head of search spam, in another video answer, responds to the question about using ccTLDs (country code top level domain names). The question was "Should I use ccTLDs for sites not targeted to those countries?"
The answer is pretty straight forward. If it is part of the list of generic ccTLDs that Google has specifically said there is enough use to warrant them to be generic, then go ahead and use them. If they are not on that list, then be warned, the site on that ccTLD may be localized to the country of the ccTLD.
Here is the video:
In the Google+ post, one person brings up the domain youtu.be, which I used above to link to the video. In that case, it would be a ccTLD that is NOT generic, according to Google's own list. But since it redirects (well, a 302 redirect), it doesn't matter much. But if the main site was youtu.be and not youtube.com that would be an issue.
Forum discussion at Google+.
Image credit to BigStockPhoto for TLDs