They are international; it's just that outside of the US the quantity of posts is much lower as people use local alternatives.

Also a large portion of craigslist here was just the personals section - once that was shut down there is basically no good reason to use it anymore, as it simply doesn't have the network effect / critical mass of users to sustain itself. The remaining users all seem to be work-related scams of some kind (probably automated) and drug dealers (probably cops).