Back in the early days of blogging and when comment spamming was still fairly small scale (compared to today) one method people used to stop a spambot was to use a CAPTCHA. The idea was that a comment spambot could not read the image and so the comment would fail and you would not get any spam. Obviously the spammers really did not like these CAPTCHA’s so they devoted resources to get around them.
In January 2004 — 5 years ago — Cory Doctorow blogged about pornography being used to get humans to solve captchas for spammers and there were scripts which could defeat different CAPTCHA’s. It is because of those scripts that you can now be faced with images that you struggle to get right. All you want to is leave a comment right?
Companies still believe in the power of the CAPTCHA and they are now very wrong to do so. Where there is a demand by those wanting to spam there is supply – and it’s less than a cent to spam your blog. At ZDNet’s Security blog they report on an industry which can solve a quarter of a million CAPTCHA’s a day.
You write a post and you would like comments. Using a CAPTCHA to stop a spammer is not going to work. If someone is writing a reply to your post why make them solve some image with distorted letters? They want to think about your post not whether that is an 8 or a B, a 1 or I or l. If people have previously been annoyed by these things they may not even bother trying to leave a comment. You lose here — your blog lost a comment.
Putting visible obstacles to commenting irritates readers and gives spammers something to overcome and the more information spammers have the more likely they are to spam your blog. This is why Akismet works as it does — keep the spammers guessing but let people comment freely. Commenting should be as easy as blogging because that is how to keep your conversations going.