I've changed my mind. The kind of naming policy that Facebook and Google Plus have is actually a radical departure from the way identity and speech interact in the real world. They attach identity more strongly to every act of online speech than almost any real world situation does.
I want to walk you through how I've come to this understanding. Because I've been obsessively listening to Philosophy Bites podcasts, I'm going to use a thought experiment.
Imagine you're walking down the street and you say out loud, "Down with the government!" For all non-megastars, the vast majority of people within earshot will have no idea who you are. They won't have access to your employment history or your social network or any of the other things that a Google search allows one to find. The only information they really have about you is your physical characteristics and mode of dress, which are data-rich but which cannot be directly or easily connected to your actual identity. In my case, bystanders would know that a 5'9", 165 pound probably Caucasian male with half a beard said, "Down with the government!" Neither my speech or the context in which it occurred is preserved. And as soon as I leave the immediate vicinity, no one can definitively prove that I said, "Down with the government!"
In your head, adjust the settings for this thought experiment (you say it at work or your hometown or on television) or what you say (something racist, something intensely valuable, something criminal) or who you are (child, celebrity, politician) or who is listening (reporters, no one, coworkers, family). What I think you'll find is that we have different expectations for the publicness and persistence of a statement depending on a variety of factors. There is a continuum of publicness and persistence and anonymity. But in real life, we expect very few statements to be public, persistent, and attached to your real identity. Basically, only people talking on television or to the media can expect such treatment. And even then, the vast majority of their statements don't become part of the searchable Internet.
Online, Google and Facebook require an inversion of this assumed norm. Every statement you make on Google Plus or Facebook is persistent and strongly attached to your real identity through your name. Both services allow you to change settings to make your statements more or less public, which solves some problems. However, participating in public life on the services requires attaching your name to your statements. On the boulevards and town squares of Facebook, you can't just say, "Down with the government," with the knowledge that only a small percentage of the people who hear you could connect your statement to you. But the information is still being recorded, presumably in perpetuity. That means that if a government or human resources researcher or plain old enemy wants to get a hold of it, it is possible.