Redundancy and Disaster Recovery - Why?
Why in the hell would Twitter need redundancy and disaster recovery plans in place? They don't really generate any significant revenue, they don't store sensitive data; hell, they aren't even a business - Twitter is a free online service whose only purpose is to give otherwise useless people a way to feel relevant.
It looks better on the books as well. This incident will be forgotten about in about 430,000 Tweets (about 1.2 minutes) and Twitter still won't have had to invest millions on redundant infrastructure.
Twitter is looking to get swallowed up at some point and whoever buys it will be buying a brand, not an infrastructure. From a whore yourself out management perspective it's a sound strategy - less overhead, less debt = easier sell, more profit.


