Quora, like many sites today, offer the option to log in with a Google or Facebook account, which may have been the "linked networks" that their blog is referring to.
A measure, Quora said it has taken to prevent further damage to all its users.
Public content and actions such as questions, answers, comments, and upvotes, and non-public content and actions such as answer requests, downvotes, and direct messages were also acquired by hackers. Quora has already begun emailing affected users. There are emails going out notifying users of the breach, but right now all of the information available is organized in this FAQ. This is not the first instance of data compromise at Quora.
Quora has said that it's highly unlikely that stolen data will be used for identity theft as it doesn't collect information like Social Security numbers or credit card details.
You can't exactly get a sense of the severity of the data breach that Quora disclosed late Monday, which came in the form of a blog post from CEO Adam D'Angelo titled "Quora Security Update". Passwords used by affected accounts will be invalidated.
It also said that the root cause has been identified, with steps being taken to address the issue. The email is an exact copy of the post on the Quora website.
To combat this breach, Quora logged all users out, and forced all accounts using a password as authentication to reset it.
He added that they have also notified law enforcement officials.
Or you could completely delete your account by going to your profile picture settings privacy delete account.