It appears that Twitter has been down for awhile. It appears to be a more serious crash than normal, because you aren't even seeing the "Fail Whale", you are just getting a 503 error, which is the error code for "Service Unavailable"
According to the tech support people at TypePad, some of the features that allow you to share posts from your blog, such as this one, to your Twitter account are encountering difficulties because of the recent cyber attacks on Twitter. On the TypePad, bloggers are seeing the erroneous message that their Twitter password is wrong. TypePad and Twitter are working on it, but don't have a fix yet.
Mashable notes that many people with both Twitter and Facebook accounts saw a problem July 30, where Twitter appeared to take over the user's Facebook wall. It happened if you had the Twitter or Friendfeed app on Facebook. Apparently, it was due to a Facebook bug, which has been fixed. Read more about it here.
C Net has information about a phishing scheme that will attempt to steal your Twitter log-in information by steering you to a site masquerading as Twitter. Be careful - you don't want someone stealing your Twitter log-in information and then proceed to make a bunch of really boring, mundane posts.
