I've seen many recent articles about "Gen Y does (or doesn't) value privacy". It's interesting, because the perception seems to be: Once all those misguided youngin's grow up, they'll realize that they need to lock down their online identity more, not less. I'm not so sure. Odd thing is, I've realized that as I get older, I'm getting more open.
In the late 90s, I started using my own name everywhere online. Some of it was laziness; "jonobie" was typically available as a username. (Counterexample: MySpace. I've always wondered if the jonobie there saw my name elsewhere and lifted it as "cool-sounding", or somehow came up with it on his own.) But some of it was that I realized that two good things happen when I'm honest about who I am online.
First, when I'm using my own name, I behave better than I might if I were anonymous. My Austin UU pastor, Davidson Loehr, once talked about living under the "gaze of eternity" as an ethical standard:
The Romans [...] taught that we should live “under the gaze of eternity,” which meant to live as though all the noblest people, the greatest souls, were watching us, then to do only what we would be proud to do under that gaze. It’s hard to improve on that as a one-sentence guide to living ethically and morally.
With the Internet and good search engines, the eyes of the future ages are always there, and using my own name usually makes me think of that quote before I do something. I don't always live up to "what I'd be proud to do under that gaze", but I at least try not to embarrass myself under it, which is a good first step.
Second, I want people to know me, warts and all, rather than to meet some photo-shopped version of my identity. Obviously I still try to show my best side (see above), but there are documented aspects of my life that no longer apply, and that's okay. I don't care if future potential employers or friends know that I was Pagan; if that affects their decision to hire or friend me, then we're not a good match. But now that I'm a secular humanist, I actually do sometimes wish that my "deluded years" weren't out there on display for everyone to see. Problem is, I have several religious essays posted that I'm still proud of and that got a fair amount of linking and reading in the Pagan community. Given the choice between leaving the essays or deleting that part of my history, I'd rather share the whole kaboodle than edit out two years of my online life. And deleting that part of my life would look like I somehow was disowning it as part of me, which I'm not.
Actually, there's also a third reason. I think secrets have an unhealthy power, and the solution is to hold as few of my own as possible. Penelope Trunk's essay How to decide how much to tell about yourself on your blog is a compelling and potent description of this. (Warning: Adult and extremely disturbing stories. It's visually safe for work, but not thematically safe for work.) I don't have anything so difficult in my past, but any hint of someone gaining something with "my" secret (even silly stuff, such as a few days ago at work when a coworker teasingly said she had dirt on me) and I tend to immediately reveal the secret. (In this case, that I once had an odd enough fashion sense to wear striped harem pants to work at IBM.) I'd rather control the story and own the risk and reward, rather than allow someone else to. I'm also in favor of companies having an open salary policy, because I think conversations around why people make different amounts is healthier than it being cloaked in secrecy.
I do still restrict two types of information to acquaintances or friends. The first is very personal medical information (though running injuries are fair game), mostly because I assume anything I post publicly is fair game for cocktail conversation, and frankly, I'm not up for that. The second is probably best defined as "topical musings or grumbles". I omit many identifying details and never use names, but if I'm thinking deeply and writing about a problem I currently have, it's pretty likely that people are identifiable in the situation around the time it occurs. I don't write things that are mean or belittling (see "gaze of eternity", above), but I wouldn't want to hurt someone inadvertently or disrespect someone else's privacy. But I find that such posts wrestle with interesting problems and are still interesting once the identifying information has long expired, and so those are the posts I'm now unlocking.