The internet is a fantastic tool for connecting with your audience, there's no doubt about that. Only one of my small collection of twitter "followers" (I still find that term amusing) has ever met me in real life. To stay away from social media altogether, or worse, have no internet presence at all, would mean missing out on the opportunity to collaborate with other writers, teachers and parents. And although there's no real data to support this idea yet, it's certainly been suggested by more than one agent that a web presence is important in building an audience of readers.
There is some information that I deliberately avoid giving out. It's the common sense stuff that police come and talk to school students about. As a parent, this is as much a matter of my children's privacy as it is my own - after all, my location is also their location. I talk about them, probably more often than some people would like, but I don't use their names or photographs. You might notice on my bio page, there's no picture of me and my town is not referred to by name. Does this hurt my sense of authenticity? Do readers feel distanced from me? Perhaps they do, and perhaps that's why Harris included a false photograph on her pseudonymous account. On the other hand, I don't believe that my picture or my location communicate anything important about the books I write or the ideas and people I care about. I'm not opposed to a photograph being included in any book that gets published, but in the meantime I'm happy for this to be a blind date.
If you're following me on twitter, you'll notice that I use the same account to post about writing, parenting and teaching. Even if you're not, you might notice that I've written about teaching before on this blog - without mentioning the name of the school I teach at, of course. I don't try to split up my identity or approach writing in a vacuum. My writing is impacted by things I've learnt from studying language and literature day in and day out at work. It's also influenced by the other people I interact with in my capacity as a parent, teacher, and even as a soccer fan.
For me, then, a false name (and I do use pseudonyms in different places on the internet) is not synonymous with a false identity. I think the most important thing about interacting with others on the web is being genuine in those interactions. Don't pretend to share their politics if you don't. Don't make up interests; someone might want to talk to you about them someday. Some writers may prefer not to share their career, especially if they're in a more private field like law enforcement, and that's fine. But I don't think it's wise to make up a false career; just don't talk about it. Be who you are, and sooner or later you'll build connections with the same kinds of people you might be friends with in real life.
A note about queries: when it comes to querying agents, do it with your real name. It's a private piece of communication (letter or email) sent to an individual, not the public. And hopefully it's the first step in a business transaction that will involve your real life bank account. If you want to publish under a pseudonym, your agent and publisher will need to be in on the secret.
Sadly, Blythe Harris did take precautions. She didn't post her location online; it was handed over without her consent. Unfortunately there isn't much you can do to avoid that kind of thing, besides having a PO Box. It would amount to never trusting anybody. But at least I know that if someone ever does track me down and turn up at my house, there'll be a trail somewhere of the amount of effort it took them to do so.