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Last night, Twitter’s DNS records were maliciously changed to point at servers that Twitter does not control. If you tried to use Twitter during that time, depending on how you authenticate to Twitter, it’s possible that you sent your user name and password to those unauthorized servers. I’d recommend that you immediately change your Twitter password.
And don’t stop there. If you use that password at other sites–a practice that’s all too common–make sure to go change it at those sites too. Especially if you use the same user name. While you’re at it, take the time to use a different password at each of those locations. Use a password manager to help you remember them if it helps. I use the excellent 1password personally, and highly recommend it.