We look at how the social networks that broadcast your location to the web, such as Twitter, Google Buzz and Facebook, are creating 'social insecurity'.
Here are five examples of the many weird new ways privacy can be violated.
1. Facebook photo tagging
You're a respectable citizen, a pillar of the community. You're active in local charity organisations. You're a senior officer in your company, and a church elder.
Your kids think you're perfect. Then your old high-school buddy posts a picture of you vomiting shirtless at a debauched punk rave in the 80s with a cigarette in one hand, a bottle of Jack Daniels in the other and a purple mohawk on your head.
He tags you, which puts that photo on your Facebook Wall. Now that photo has been shared with your mother, your kids, your boss, your colleagues.
Once seen, it can't be unseen. If anyone copied the photo, it's now 'out there'. Forget about ever entering politics.
2. Google Buzz people harvesting
When you fire up Google Buzz on your iPhone, Android phone or - soon enough, presumably - any smartphone, and hit the ‘Nearby' button, you get a list of posts from strangers listed in order of which is closest.
Their usernames can lead to their profiles, which probably enables contact via email (like Craigslist, email addresses can be private, but anyone can still send email through Profiles).
What's to stop any business from firing up Buzz every day and harvesting contacts of people who come to the neighbourhood?
3. Street View evidence gathering
The chances that you personally will appear on Google Street View round to zero.
The chances that a great many people will be exposed on Street View doing something embarrassing round to 100 percent.
Thanks to social sharing, every transgression captured by a Google Street View van will be exposed, broadcast, shared and stored forever on hundreds or thousands or millions of hard disks across the world.
If you're one of the lucky few caught doing something unpleasant on Street View, people you know will find out about it. And funny photos are forever.
4. Social group mixing
It's easy to forget who's following you. Facebook users often post compromising information.
Somebody might, for example, report the he called in sick to go to the beach - forgetting that his boss is one of his Facebook friends.
Young people might have peers in mind when they post, and forget that mother is lurking.
And on social networks like Twitter or Buzz, it's possible that people you know are following you under a pseudonym.
5. Set-it-and-forget-it sharing
New social services come along all the time. We sign up, try them, then forget about them when newer and shinier things come along.
For example, Google came out with the Latitude location service a long time ago.
Did you try it? If so, did you turn it off? Are you still trackable?
The harsh reality is that most of us have no idea if we've left a trail of privacy-compromising services in our wake.
McNealy was right of course. Theoretically we have zero privacy. A motivated and skilful person or organisation can always learn things about us that we'd rather keep to ourselves.
It's still a good idea to practice common sense when using the internet.
Don't blather information that could be useful to crooks. Be careful about what you share, and whom you share with.
Take care in broadcasting your location, either manually or automatically.
But even the most meticulous anti-social-networker can't really achieve true privacy.
The strange new reality of 'social insecurity' is this: The best we can do is make the violation of our privacy a little less convenient for those who would exploit us.
See also: 10 Facebook & Twitter privacy faux pas