There are plenty of valid reasons for not wanting your online activity and information to be packaged up for anyone who wishes to “follow” you. Many people who use one or more of Google’s services never intended for, say, their Google Reader information to be connected to their e-mail addresses. Some of them need to keep that information unlinked so that, for example, abusive ex-husbands and threatening strangers can’t find new ways to torment them.

It’s easy to believe that open access to personal information is mostly harmless, and that stalkers only harass drama queens and women who “put themselves” in dangerous relationships offline. It may be especially easy to believe this if your worst communication experiences online have involved flamewars and nasty emails.

Here’s the thing. I’m using Google Buzz, albeit carefully and tentatively, but a year ago, I wouldn’t have been doing so.

For a long time, I kept my online identities as fragmented as possible to make it harder for strangers (or the wrong acquaintances) to physically find me in non-public venues, or to see what I was posting under other names. Why? Because when I was an undergraduate ten years ago, two men with whom I did not want contact found me—found my dorm and room number and supposedly private unlisted telephone number. This information was “confidential,” but that didn’t keep me from getting surprise calls late at night, including one from an unstable young man I had known briefly in high school who happened to believe that I was causing him to be spiritually attacked by demons, and who now knew exactly where I lived.

Those calls—demonstrations that people who did not have my best interest in mind wanted and could easily obtain my personal information—shaped my online habits.

About a year ago, I realized that by speaking at various conferences, I had already left a trail for anyone who cared to bother me. So I stopped asking people to remove my last name from the captions of photos posted online. I let my anonymous accounts drift toward my identifiable ones. I started to publicly talk about travel plans. The fact that I’m approaching my mid-thirties and have been in a committed relationship for ten years has shielded me from a lot of random harassment, but I remember what it felt like to be so vulnerable.

It’s unconscionable for Google to connect up disparate accounts and circles of online activity that happen to be associated with a Gmail address by default. It is even less acceptable that they have provided such inadequate ways of opting out, aside of deleting all information associated with any Google product or service or any product or service they eventually acquire. But most Gmail users won’t object, because they’re used to having their privacy treated as a non-issue by the companies with whom they trust their information. Nevertheless, it’s wrong. And for some people, especially for young women, sexual and ethnic minorities, activists, and anyone engaged in controversial communication online, it’s dangerous.