There's a long discussion of it here.
There are a number of comments by the author of the original post, Yonatan Zunger, a chief architect at Google, that make me bang my head on the desk repeatedly. I can't figure out a way to link to the comments directly, but here's one that particularly caused head-banging:
We thought this was going to be a huge deal: that people would behave very differently when they were and weren't going by their real names. After watching the system for a while, we realized that this was not, in fact, the case. (And in particular, bastards are still bastards under their own names.
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