TLDR; I give my experience with online identity and ideas as to where it is headed. Over the years I have held several monikers on the Internet. Not only is it easy to conceal an identity but it is seemingly encouraged by various registration forms. The simple absence of Your full name: as a hard requirement panders to people's creative expression.
Until recently, the masked Internet was thriving and mainstream. I say until recently with reluctance. There is still a thriving anonymous community but the majority of people (on Facebook, Twitter, Google) are using their real names to identify themselves.
People going by their real names online used to be rare, especially in online social interaction. The concept of using your real name online wasn't bad - it just wasn't necessary.
For many of the pre-social network internet inhabitants (irc, aol, usenet, hackers, 3l33t, etc.), having an identity online tied to 'real-life' was an offense. When social networks embraced and required the use of real names, there was somewhat of an outcry. It was an affront on one of the core positives of the Internet; the freedom to express oneself.
Having a username like th3j35t3r or TimBL up to 2004 almost guaranteed anonymity. It was fairly easy to sterilize one's online identity from the day-to-day family and social life. If you said something controversial online, it didn't echo out into
The computer was essentially a black box where anyone could be and say whatever they wanted, with no consequence. A passionate secret for the technically inclined and a preservation of self. For many it was 1984's hidden notebook.
That snapshot has changed, and online identity is now a complex and mysterious subject.
For the majority of people, having an anonymous identity is emotionally rewarding. It isn't a serious security precaution or a preventative measure arising from paranoia. It's a luxury pair of sunglasses and not a Kevlar vest.
I wear those sunglasses and occasionally I see people wearing the vest. (I have also tried to wear that vest but the weight of it is annoying when I know my head's still exposed.)
Having a purely anonymous identity online is harder because tracking people is easier. A relatively inexperienced geek can find out who someone is without writing a single line of code. Root passwords to secure systems can be obtained via social engineering. Cookies, analytics, cross-site tracking, persistent multi-site sessions, etc. have made it incredibly difficult to have any control over who you are online. It sounds pretty bad for securing information, let alone identities.
Being anonymous was great, until I wanted to do some online banking...
This isn't a doomsday manifesto. Today, being controversial or outspoken is fortunately passé. Facebook has made us all a little more accepting of everyone else's crazy.
As much as we're losing anonymous, we're gaining acceptance of transparency.
So there you have it, a glimpse into my conscience - online and transparent. Fortunately for me, no one reads it - so I don't fear being judged. (I track my readership with Google analytics)
As for the people that wore Kevlar vests: they've just had to spend a lot more time building better vests. They now build and sell the vests. My point is that if you want your pseudo-identity to be really secure these days; you had better devote your career to it or pay someone that has.
We could also accept that there is no such thing as an unbreakable safe and that most people don't care to read our diary anyway. We're too busy reading Aldous Huxley's wiki.