Quora, the Mountain View, Calif.-based question-and-answer site, disclosed a breach late Monday. The company originally discovered it on November 30; hackers got access to users’ names, email addresses, and activity, including behaviours on the site (e.g., downvotes) and private messaging. It’s recommended that users change their account passwords. (Mercury News)

Talking point: This is a significant breach for Quora, as 100 million of its 300 million monthly users were affected. The news comes three months after Quora raised US$85 million at a US$1.8-billion valuation to expand internationally and grow its ad business. The lucrative nature of that ad business is based partially on harvesting exactly the kind of personal information that was just hacked. That won’t necessarily be a problem for Quora. After all, the news comes just two months since Facebook, one of the largest digital advertisers, disclosed its own breach, affecting 50 million users who had their personal data compromised.