It is reported that the hack was performed by a group identifying itself as the ‘Iranian Cyber Army’. The questions we need to ask now are: Was this the group that was really responsible? Or is someone trying to smear them? If it was them, why? Is it to prevent free speach in Iran? Is something big about to happen?
The most important question to many people in the west, of course, is — did they get any data?
Nobody really knows. Few media outlets are mentioning anything related to comprimised data.
The real answer is that nobody has a clue if they have any login data/personal data. My take is that if they are capable of modifying the DNS record to their own servers — then they would have been clever enough to harvest all of the information being sent to the twitter domains. This includes all data being sent via any API using login credentials for third-party site interaction.
If they were prepared and skilled, then it would have been a relatively simple task. Which means that we have tens of thousands (possibly even entering hundreds of thousands) of accounts that are potentially comprimised, If they were able to listen and log the data being sent to them.
If this is the case, then I advise you to change your password immediately. Even if you have not interacted with the API yourself in the last 24 hours, it is entirely possible that your login credentials are being used on a gadget/widget or third party site that MAY have posted login information while the DNS was comprimised, meaning your account is also potentially comprimised.