Does e-mail obfuscation really make automatic harvesting harder?

Question

Many users and forum programs in attempt to make automatic e-mail address harversting harder conseal them via obfuscation - @ is replaced with \"at\" and . is replaced with

Answer 1

It does make it harder to a degree, but the simple ones used by users even today (the [dot] and [at]) are obsolete and can be captured easily using a simple regex by spammers.

Using something as simple as an image would be helpful and readable for the intended human reader without effort to 'decrypt' the encoded email id.

Contact email:

If you are still paranoid about character recognition equipped spam bots, them something like this would be effective.

It uses optical illusion as an advantage to complete letters in the human mind that cannot be easily understood by computer vision. Applying CAPCHA-like overlay can also help, but I doubt you need to go that far.

Answer 2

It does make it harder but there are so many really smart scrapers that it probably doesn't help a lot, since the big spammers are using the high quality spam tools.

Answer 3

It's analagous to putting a "protected by ADT" sticker on your front door.

Will that prevent a talented burglar from entering your house? Of course not.

Will it make the house next door with an unlocked door and an iPod in the window a more compelling target? Pretty likely.

A simple unobfuscated email scraper is going to get TONS of emails as it is. Maybe a very simple regex to pick up very common obfuscation methods is worth the effort. Past that, you're spending a lot of time trying to decipher an increasingly small percentage of emails.

All that to say, having some clever obfuscation is probably worth it.

For the record, my email has been on my public resume in plain text for years now, because I use gmail, which has a spam filter that works.

Answer 4

To provide a literal answer, yes, harvesting obfuscated addresses is harder than harvesting standardized addresses. The real question is whether the extra effort will be put in by harvesters and if the (major? minor?) barrier to the harvesters is worth the possible problems for your users.

If you are going to scramble addresses or otherwise transpose them away from the standard form, you should avoid being consistent in how you do so – at least on the same site.

For example, if every email address on a large community site is reversed in the markup and rendered properly with CSS, or token-replaced (@ becomes 'at'), or any other predictable method, the harvesters will just write a thin adapter for your site.

Think of it this way: if it only takes you one line of code to "scramble" them sitewide, it will only take the harvester one line of code to "unscramble" them for your site. Roughly speaking.

In my opinion, spam has become such a problem and so many DBs have been turned over that we're beyond hiding our addresses. Instead, consider looking at Defensio and Akismet, etc, to help classify and block spam.

Answer 5

I was wondering why nobody mentioned ALAs solution so far.

Roel Van Gils wrote an Article about Graceful Email Obfuscation in 2007

Graceful Email Obfuscation is simply a JavaScript Email Obfuscation technique with a contact form fallback.

1. Email addresses are obfuscated by converting them into a url poiting to a contact form and applying a ROT13 transform
2. mailto:mail@example.com → contact/mail+example+com → contact/znvy+rknzcyr+pbz
3. Via javascript contact/znvy+rknzcyr+pbz is converted back to mailto:mail@example.com
4. If no javascript is available, the browser will open contact/znvy+rknzcyr+pbz as a fallback. The contact form will know where to send the email because of the url.

http://www.alistapart.com/articles/gracefulemailobfuscation/

Answer 6

It will be difficult for the spammers as well as your users to identify the email address.

A nice article from wikipedia on Email obfuscation or address munging

One common way of hiding email from bots and spammers is to create an image containing the email address. Facebook does this, for instance. Now, using images for email is inherently bad for accessibility, because text readers will not be able to read it. But even otherwise, there are several free character recognition programs that do a pretty good of decoding such email-images.

From here