The why is easy.
The what to do? Not so much.
Why is it a bad idea? Simply put: spam and people who would abuse your email address and possibly even you.
Spam, spam and more spam
Anything that will put your email address on to a publicly accessible web page will in all likelihood cause you to start getting more and more and more and more spam.
Why? Because one technique that spammers use is to visit all the web pages and online services that they can and collect anything that looks like an email address to add to their mailing lists.
Here’s an example: firstname.lastname@example.org. Now that I’ve published that email address on the web on this page, even though it’s the only place that the email address has or will be officially mentioned, it will now start getting spammed.1 Just because it was published on a web page and it looks like a valid email address.
So when you include your email address in an online posting, say in a Facebook post, on a discussion board or even in a comment here on Ask Leo!, you’re almost literally asking for spam.
Don’t do it.
Particularly on social media another risk of posting your email address publicly is that … well … people can see it because it’s public.
If there are people that perhaps you don’t want to have your email address, you just gave it to them. That friend of a friend? The person stalking you? The person who takes offense at the comment you posted? They can all now start abusing you via email, if they so choose.
They may not. In fact, most people don’t. But it can happen.
The internet isn’t always a friendly place.
Forms that require an email address
You’ll notice that in order to post a comment on Ask Leo!, you’re required to provide an email address. But notice also, that that email address is not published on the web page (in my case, if you use a valid email address, it’s simply a way for me to follow up with you directly should I have a question about your comment).
But be careful! Not all weblogs and discussion forums hide your email address. Many turn right around and put it on the web page for all to see. Including the spammers. And others simply use it to, you guessed it, start sending you spam.
Before you post anywhere, be sure you know what’s going to happen to your email address when you do.
Mailing list archives and other information leakage
Are you a member of a mailing list? Does that mailing list have a publicly accessible online archive? Then your email address may be available to the spammers for harvesting. Ever post on Usenet? The email you used is probably already in the spammer’s lists.
An early Usenet post “before I knew better” is the reason my wife gets hundreds of spam per day.
So use a fake address – or better yet, don’t use one at all.
Obfuscation is the second best defense
Now, what if you need to post your email address in a publicly accessible place? There are several techniques for obfuscating the address. Here are a couple of my favorites:
askleo at gmail.com
The first you’ve probably seen already in other places. It simply requires that you, as a human, realize that the ” at ” needs to be replaced with “@”. My fear is that this technique is also fairly easy to decode by computer and the spammers will soon catch on.
The second requires some thought. If you sound out “seeohem”, you’ll realize that it sounds like c, o, m. “com”. Hence, you realize that the “.seeohem” really means “.com” and can make that translation when you type in the email address.
The biggest drawback to these approaches is that the email links are not clickable. Anything you can click on to get an email address, the spammers can use to harvest it. Even copy-paste doesn’t work, for exactly the same reason.
But protecting yourself from spam is important. And not asking for more is even more important.