I feel that this is becoming a standard narrative. SV company comes up with an idea, decides harvesting lots of user data is how they will monetize. VCs pump in a lot of money and expect their returns, so company is now forced to collect even more data aggressively (the sign-in wall that many others have pointed out is an example of this). VC pressure causes company to "innovate" fast, most likely trading off security for new features in the meantime. As this progresses and they become more valuable, they are then targeted by hackers, which causes some type of compromise of users' data.
Quora is an intimate medium — tied to real names, real and often deep interests. It's especially bad that this happened.
There needs to be a better way to realign incentives in this ecosystem, otherwise this story will repeat.