The attackers are believed to have accessed the following information:

• Account information, e.g. name, email address, encrypted (hashed) password, data imported from linked networks when authorized by users.
• Public content and actions, e.g. questions, answers, comments, upvotes.
• Non-public content and actions, e.g. answer requests, downvotes, direct message.

The company said it’s in the process of notifying affected users, logging out those whose accounts have been compromised and resetting their passwords, and investigating the attack with the help of a security firm.

The attack may not cause much direct monetary loss to users, since Quora doesn’t store credit card details or other payment-related information. If the incident has irked you enough to delete your Quora account, you can find out how to do so here, and also learn about resetting your password and obtaining a copy of your data from the site on this attack FAQ page.