Comments on: Captcha Takes No Prisoners

By: David Spector

David Spector — Mon, 20 Apr 2009 17:40:58 +0000

Missing from your complaints: that image-based CAPTCHAs cannot be completed by blind and visually impaired people (as many of us older folks are). This is not merely an inconvenience, but an abrogation of the civil rights of this (as yet not legally recognized) group of people. Shouldn’t everyone have the right of equal access to resources in an egalitarian society?

Text CAPTCHA works fine. I maintain a number of websites having Contact Us forms that show a random 3-digit number and ask the user to copy the number into a text field on the Contact Us form. While it is certainly not difficult for a spammer to create a bot that will defeat this mechanism, it has not happened in the four or more years that these forms have been in existence. And even when it does happen, all I have to do is modify the task slightly to make the bot fail again.

By: David Bradley

David Bradley — Fri, 23 May 2008 10:25:15 +0000

That’s right emp, that’s why I suggested fellow bloggers not use them.

By: emp

emp — Fri, 23 May 2008 08:25:20 +0000

Captchas either approach unreadability and thus, the frustration level of the users or they are crackable. View the PDF with instructions. emps last blog post..Captcha Breaking in detail

By: David Bradley

David Bradley — Mon, 12 May 2008 12:39:14 +0000

Thanks for the feedback Robert, yeah IP blocking in .htaccess is sensible for some of the more prolific spammers.

By: Robert Irizarry

Robert Irizarry — Mon, 12 May 2008 11:46:28 +0000

David – I’m with you on captchas – don’t use them. They discourage commenting and there are better ways to deal with automated spam.

ChemSpiderMan – I’m a big fan of Spam Karma as a means to control spamming. It contains configurable rules that check for a variety of conditions that indicate that a comment is spam. There’s even an Akismet plugin for it that will send a borderline comment through Akismet as a final check. There are other anti-spam plugins but I haven’t looked at any of the newer ones since settling on my current solution.

If you’re willing to go even further, there are a number of things you can do in your htaccess file to reduce the amount of spam and other unwelcome activity. You can block ip blocks, site copying apps, comments submitted without a referrer, etc.

By: ChemSpiderMan

ChemSpiderMan — Tue, 06 May 2008 11:13:53 +0000

I know you weren't suggesting we let garbage through. I'm looking for an approach to block the spammers though. Can you suggest some "transparent captchas"? I can take a look at. Thanks David ChemSpiderMans last blog post..Jean-Claude Bradley Posts About New Trends in Science and Mentions ChemSpider

By: David Bradley

David Bradley — Tue, 06 May 2008 07:44:14 +0000

ChemSpiderMan, my suggestion not to use a captcha was not to suggest that any site let garbage through. A site owner must have full control of content that appears on their site (unless they’ve deliberately set things up to be 100% community led, but even then you still need some form of editorial control). Obviously, depending on the work load manual filtering of spam that slips through is the only way forward. Unless you can find a transparent captcha (there are some) that works 100%.

By: ChemSpiderMan

ChemSpiderMan — Mon, 05 May 2008 16:44:28 +0000

AS you know we have allowed annotation of records on ChemSpider. We DON’T ask for a login. Look at the result. Scroll to the bottom of this record: http://www.chemspider.com/Chemical-Structure.7475.html

See the “garbage”. Spammers….

We are considering switching on a captcha. What would you recommend instead?

ChemSpiderMans last blog post..Care in Nomenclature Handling and Why Visual Inspection Will Remain