I have to take the minority position and stand up for Quora here. I'm a huge fan of the service, and though I agree this latest move was a mis-step, I remain a loyal Quora user.
Unlike you, I've gained a ton of value from it. Unlike the trivial discussions or content spam posted on Facebook or Twitter, Quora features tons of interesting conversations. The closest comparison to it might actually be Wikipedia, at least in terms of general scale of ambition.
It's the one online community I've found that I think is better than Hacker News (though admittedly the quality of discussing has slid as the audience has grown wider). There's few other places where a question about politics might be answered by a Washington insider, or a question about startups might be answered by a top name Valley VC, or a question about snipers answered by an actual sniper.
Their real name policy has generally been fairly sensibly and sensitively implemented (http://www.quora.com/Why-has-there-been-an-outcry-against-re...) - they've always allowed anonymous posting, and they've been more flexible on the definition of "real name", than, say, G+. For example, danah boyd is able to post with the legal, lowercase form of her name.
Whether they'll begin bowing to advertisers once they need to monetise of course remains an open question -- but I'm hoping they can find alternative revenue streams. For example, a lot of consultants post answers on there to gain clients -- that's an example of the concrete monetary value Quora creates, and if they can capture some of that value they can build a great company without stooping to Facebook-style data mining controversies.