A while back, Twitter announced that it was amending its policies to be able to block accounts or remove content on a country by country basis. The idea was that if something was illegal in one country, it could be removed there without affecting the rest of the site.
Now, it's making use of those new rules for the first time, by blocking access to an account linked to a neo-Nazi group in Germany.
Twitter received a request from German authorities to block a particular account and the tweets coming from it inside the country and the company complied with the request. However, the content is still available elsewhere.