Today, while looking around MyBlogLog: New with me admin, I was stunned to see no updates from Twitter since last couple of hours and all twitter requests are generating 503 errors. Got relieved, when I found, nothing is wrong with our twitter crawlers rather twitter is down. 
In case you haven’t noticed, twitter was down for more than a couple of hours, precisely from 22:12:15 (5 Apr) to 00:42:46 (6 Apr) PST.