This was a bad idea when it was called MS passport and still a bad idea when its called openId.
No matter how many times I see that FUD and deliberate misinformation equating Passport and OpenID, I am still astounded at the intellectual dishonesty of it. Bravo, Mikester!
So choose carefully, and focus on those things that best represent you.
Being schizophrenic, I love this topic. j/k, I’m not really schizo… or am I ?
Opinion only - it’s refreshing to know that I mostly use the online environment and multiple identities to attempt to solve technical issues. I’m a fiend for technology and science. Whether it be school work, or actual employment, the odds are you can find me researching technology. I try to stay away from social networking, sometimes it can be fun to chat with friends(of whom the majority I am friends with face-to-face); I’m never really that bored when I’m online - which is for very long periods of time. When it boils down to personality, I’d like to think you’re never gonna learn anything else about me other than the technical advice I give or the education I seek. To me, online == resource. If I’m bored I’ll go play a game or walk away from my system. In technical forums, I find that using the same handle increases ones credibility… although I’m not sure exactly how… now I’m bored…
I’ll guess that most of those sites have content that is the same as the others. I have a feeling the people use those different sites to advertise their blogs and spread it to different crowds they don’t reach on their blog and each site.
If someone wrote a tool to post the same content to each site it would be a very useful.
XBox Live is a nice solution to this problem for online gaming. On PC gaming (and every other console that now supports online gaming), you have a potentially different identity in every game you play (depending on how lucky you are at getting your name of choice). Even if you get the same name in Quake and Team Fortress, there is no way for other people to know they are t he same person. XBox Live introduced the concept of the Gamertag - a name, a short bio, a list of friends, a history of game accomplishments - that follow you around in EVERY game on the XBox platform (and now stretching into Games for Windows).
I didn’t occur to me how important this is until I’d used it for a while, and then tried to use platforms that did not support it.
Doesn’t Curly’s Law (http://www.codinghorror.com/blog/archives/000805.html) (“one thing”) apply in this case too? Instead of trying to immortalize yourself on dozens of sites, just focus on one and let that be the gathering place for your readers. Jeff does that well here. The Vertigo RSS feed was another avenue of his, but I don’t care read that one - 1 feed per blog author for me. I have enough as it is.
foaf
We use multiple identities because there are some, nosey, creepy, vindictive stalkers who care way too much about your other hobbies and interests. They’re eager to dig for absolutely anything to discredit, humiliate, or shun you.
I like things being centralized and distributed at the same time.
ISP’s should be forced to be completely protocol neutral, so I can host all my own social networking stuff without doubling my bills.
On the other hand, I choose to rotate a list of website that I frequently update to (say 6 out of 10 only at any time), so if someday I feel tired/distracted and wish to disappear from the web for a while, I’d save the trouble of explaining… 
I know of someone who use different login name to represent her different personalities. So by looking at the name she use to login, you can roughly judge how is her mood, and what topics she is interested to talk with. That’s IMO quite convenient.
I am the man who doesn’t exist!
I have no “blog”. I believe a team of psychiatrists might be able to help someone who wanted to read my “internal monologue” posted to twitter but I don’t want to be sued to pay the bills. Everyone I know who has a myspace page only got it because someone told them to, and it gets updated at most once every alternate lifetime anyway, and I refuse to be that sad.
So, according to the “when you’re interviewing people you should check them on google” crowd, I don’t actually even exist, yet alone deserve to ever have a job.
This is a good thing. Without that filter, I might risk being stuck with people psychologically incapable of surviving without their internet connection. 
“I struggle to write one lousy blog four to five times a week.”
Nope, you struggle to write one thoughtful, interesting and relevant blog four to five times a week.
Your on-line identity is as simple or complex as you choose it to be. As others have said for many there is no single on-line identity. Each name you use or site you blog represents a either slightly different or majorly different part of your thinking.
I have 4 different sites that I blog and 5 different messenger names.
I choose to have 4 blog sites because I want to share specific points of view when I lbog and try to keep in the same neighborhood on each site.
There is still a lot of misconception regarding openID. Here are a couple links that helped me understand and adopt the technology.
http://lifehacker.com/software/technophilia/one-openid-to-rule-them-allor-not-302156.php
http://ilikeellipses.com/category/openid/
@M Kenyon : centralized big databases are evil; single point of failure. With the abysmal security out there I don’t want to make the job of an identity thief easier than it already is.
The “here, look at 30 sites I visit for my personal information” is silly, though. It’s not like there’s no overlap, and it looks sort of like a desperate “be my friend/talk to me, any way possible”. A much better way is simply having your e-mail address there or some sort of contact form. There, centralized and solved.
The only thing I could think of to add besides that would be specifically for media, and you don’t need a dozen of those; just pick the most convenient and your visitors will have to bend over.
Anon said: The world would be a nicer place to live if people spent as much time developing their relationships with their neighbours, their local communities and their work colleagues as they do developing their online identities. If people were as concerned about their real relationships as they were with their online avatars…
This is what concerns me. I have a blog related to my job. I am on facebook to keep up with my kids away at college. I’m part of ning, to participate in a work-related program. I have an IM screen name. I have several email accounts, so I’m online. But I have noticed that many people seem to be uncomfortable with personal interactions. I think it’s lack of practice. If they can’t alter the environment to their own personal requirements, (listen to their iPod with their own music instead of nasty elevator music, talk with people of their own age and interest group) they seem to become nervous and eager to physically leave the situation. This hurts “real” community building, IMO.
For many people, this may not be a problem. But I am also involved in volunteer groups that actually go out and help real people in their homes. Can’t do it virtually, gotta have interaction skills. Real leaves need to be raked out of real yards. Real food needs to be taken to food pantries for real people to eat. I work in a community garden - real weeds have to be pulled from around tomato plants to get tomatoes.
Working on these projects with people builds strategy skills around accomplishing the tasks, diplomacy since everyone disagrees now and then, patience, because some people just require that. It appears to me that these skills are getting rusty with disuse and it scares me. We can’t just go offline when things get hard in real life!
A Blog is an “Avatar” not the real identity.
You are actually making a logical error in trying to make the words and letters meaning the same as the actual representation you have about your self.
It isnt.
Its just an Avatar, a representatation of your own representation of you ;).
I totally understand you – I struggle to READ it regularly, not even mention writing anything similar. But I never miss any part of it, even if I read it with delay (like this one for example) – it’s certainly NOT LOUSY.
You’re doing a great job – keep going! 
I try not to have an online presence at all. I have a facebook account, even there all the info fields are left blank intentionally. People I don’t know, have no need to know my interest in books and music, nor do I feel the desire to broadcast them.
There’s a blurb about me on our university website, but the people that wrote it didn’t even get my job description right.
I have one identity and it’s mine not the worlds.