The conversations around required unity of identity online keep continuing; but to me it's this clear and simple: You can have as many email addresses as you want, and you use them as you want them; why should social network personas/identities be any different?
When you send a message from your work email, you speak in one voice; when you text from your phone, you speak in another.
Online communities should be no different in terms of audience and participation and voice.
Fred Wilson put up a particularly smart post on the topic, with a fiery discussion: Following Facebook Down the Wrong Path. The sharp, funny commenters who post pseudonomysly on his blog prove the value of identities that are contextual to their online communities.
Yes, forums that breed trolls are bad, but that's a separate issue, and not one that insisting on real names on Facebook or Google+ will cure. Moderators, active commenters who vote people up or down, the banhammer: there are many ways to deal with trolls beyond forcing users to wear one identity across all of time and space.
My prediction: the future of social media will be won by platforms that allow people to establish many identities, to wear as they please.
The social platforms that will own the future will:
(1) Create better communities: more people will speak more freely in more voices in more places.
(2) Make the market for monetizing social speech bigger, because the speech and the communities will be better.
Cory Doctorow lays out the single identity issue as just an us vs. them thing:
"The first duty of social software is to improve its users' social experience. Facebook's longstanding demand that its users should only have one identity is either a toweringly arrogant willingness to harm people's social experience in service to doctrine; or it is a miniature figleaf covering a huge, throbbing passion for making it easier to sell our identities to advertisers.
Google has adopted the Facebook doctrine at the very moment in which the figleaf slipped, when people all over the world are noticing that remaking ancient patterns of social interaction to conform to advertising-driven dogma exposes you to everything from humiliation at school to torture in the cells of a Middle Eastern despot. There could be no stupider moment for Google to subscribe to the gospel of Zuckerberg, and there is no better time for Google to show us an alternative."
I think this is exactly correct: On the internet, when you create an identity in a community, nobody knows you're a dog, or a mermaid, or a robot dinosaur, or a mom, or ... anything beyond the knowledge you drop and the interactions you share.
People/identities who add value will be leaders/contributors in a community; people who don't will not be.
It matters little to a community if a contributor's name is Lady Gaga, Madonna, Grimlock, or Marie, Queen of Romania; what matters is the contributions.