Thing is...I find that spam from the USA is almost always easy to remove. They always include an "opt out" button at the bottom of the mail, and it works - probably due to legislation.
However.....BRAZIL, damn that country has given me the zigg. I get email adverts in Portugese originating in Brazil (.br) all the time - probably 10 to 20 a day. They started very suddenly, so I think some Poro sold my email address to a bunch of Brazilian clients. They have an "opt out" feature, but trying to opt out never works grrrr. I have tried bouncing the emails (Mac OSX mail), but that does not deter them. They always come from different company names and different email addresses, so I cannot use the advanced features of mail to block them from entering my inbox, and send them to trash. I now ignore them and delete, but they keep coming.
Even worse, is it's all in Portugese, so these spam adverts are of zero benefit to me.....just a source of extreme frustration.