I sometimes tweet in Chinese as it's even more succinct than Japanese. I don't actually write Chinese, but some tweaking to and fro in Google Translate means I can come up with <140 characters in pidgin Chinese that when machine-translated back into English produce intelligible English sentences of 300 letters or more. Unfortunately it doesn't seem possible at present to tweet e.g. http://is.gd/xxxxx forwarded to http://translate.google.com/#zh-CN|en|試験 as the 漢字 don't make it across, but it's only a matter of time until someone produces an app to do this automatically, and thereby effectively smashes the 140 character limit.