I have heard all of the arguments but if you're still active on twitter without a backstop on any other active backup social networks, after the events of the last week, I mean, come on.
@hacks4pancakes I only know one person that was on Twitter for a long time and made it her primary social media channel. I think she was on of the first 10,000 users. So I could see if she didn't have a backup account. I would think most people migrated to Twitter from another social media site. If that was MySpace, well, there's no going back there...it's the ghost of Twitter Future...