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Would post your phone number on a bathroom wall? Then why do so many people do the internet equivalent?

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This is Leo Notenboom for

I'll start by apologizing.

I'm sorry if I sound annoyed. In reality, bemused or somewhat disappointed would be more accurate.

Let me ask you this: would you write your phone number on the wall of a bathroom? Or maybe your email address? Well, of course you wouldn't. In fact, these days you probably want to be careful about putting your contact information out on anything viewable by the general public - anything from a newspaper want ad to a lost pet poster.


Because there are people out there who will abuse that information.

And nowhere are there more people like that than on the internet. The level of anonymity the internet provides allows people to say, and do, just about anything to anyone without consequences.

So why, why would you post your email address or your home phone number in a comment on some random blog? You're inviting the trolls of the internet into your home, onto your phone and into your mailbox.

And yes, of course I'm specifically talking about my random blog: Ask Leo!. At least a couple of times a week I end up editing someone's comment to remove some amount of personal information. Even though I clearly state in the instructions for commenting that you should not post an email address - it happens all the time.

Besides, you should know better.

With all the talk about spam and how email addresses are harvested from web sites, and with the constant stream of questions I get from people trying to keep or breach privacy - I'd expect more people would get it.

Identity theft doesn't surprise me in the least, given how freely so many people share personal information. No, posting your phone number won't lead to identity theft, but the mindset that allowed you to post that phone number in public place on some random web site will probably, someday, lead you to hand out more sensitive information to people or places where it just shouldn't be.

And yes, I just compared Ask Leo! comments to a bathroom wall. In fact, the entire internet is that bathroom; anyone can and will walk in and see what you've written. Anyone.

So, to be super clear: don't post your email address in the body of a comment. Don't post your phone number or private information anywhere that's publicly accessible.

It's just that simple. I'm still not sure why more people don't get it.

I'd love to hear what you think. Visit and enter 11235 in the go to article number box and leave me a comment. While you're there, browse over 1,000 technical questions and answers on the site.

Till next time, I'm Leo Notenboom, for

Article C2959 - March 11, 2007 « »

Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?


March 16, 2007 7:21 PM

I agree with you 100%

Glenn P.
March 9, 2010 11:42 AM

Personally, while I'd never give out my phone number, I just might give my E-Mail address on a public message. The main issue is not one of privacy: the issue is one of image. The downside to not providing your E-Mail address -- and the one which you simply fail to see -- is a serious loss of credibility. People simply tend to give far less credence to those who are anonymous -- to people who are unwilling to identify themselves. Those who are willing to put themselves "on the line" by divulging their E-Mail identities are simply looked upon as having inherently more legitimacy. E-Mail is not nearly as personal as phone messages, and despite the risk of additional Spam, it can still be filtered. So in some cases, I'll still add the E-Mail and bide the "danger" of added Spam.

It's a "cost/benefit" analysis. You're opinion is appreciated, Leo. But kindly stop denigrating mine!

March 9, 2010 1:49 PM

Very good points; relative to todays circumstances. It would be a fair call to suggest todays youth, posting, jokingly, personal information and pics of friends throughout the public domain - facebook, myspace, youtube, etc, are not considering what will be, in future technology.
Have a look at the last 10 years. OK, big call. Then look where the internet has come in 5 years - massive search abilities. You can nearly find anyone. How many of us have searched for old school mates, and found them.
Think about the future. You jokingly take a pic of your best mate half nude while camping, post it, all have a big laugh, and that's it. Now think about new technologies like at international airports with face recognition. Everything, EVERYthing posted on the net, stays on the net, and what if that mate from the camping trip was to enter a high profile position and future common search tools included face recognition and he was 'discovered' again.
A really simple, single case scenario, but generalise that and it can be applied to all postings on the net.
What ever you post, be prepared that it is being copied and stored somewhere, and future technology will make it available.
Todays gigabytes was like yesterdays kilobytes - nothing to store, transmit and search.
On the other hand, if you plan to have an online life, there are so many options for disposable contacts, including free throw-away email addresses and cheap mobile phones - a SIM card is like yesterdays disposable cameras.
This could be a mammoth forum - the future of online identity. I can wait to read everyones opinions and tricks and tips.

:: Thanks for the site Leo - hope you enjoyed your visit to my home here down under.

Annonymous - LOL.

Ravi Agrawal
March 9, 2010 9:21 PM

Well, if you are so inclined to post your email address, use masking techniques that will fool a spam harvester. Like without the y. That way, you have posted your email address too with the spam bots going nowhere :-)

Or still another way -- 123 period xz (ad) hotmail period com & so on.

However, nowadays every blog / comment has an option to enter the email address which will never be shown to search engines or will only be available to the writer of the article. So guess we are pretty safe here.

Moreover, each Blog / Post can be monitored using RSS Feeds.


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