An interesting — but unfortunate — statistic from this site.

One of the biggest challenges to bloggers who allow comments on their blogs — other than dealing with immature, know-it-all asses who can’t write a civil sentence — is comment spam. It generally comes from three sources:

• Automated spambots that are programmed to post comments on blogs. This accounts for more than 90% of the comment spam out there.
• Real people who manually post comments that promote their products, services, or websites.
• Pingbacks from blogs built by scraping content from other blogs, primarily to attract hits to other links on their pages.

I wrote about comment spam extensively on my Maria’s Guides site when I was regularly providing fresh content about WordPress. If you’re a blogger, you might find the following posts there interesting:

• All Pingbacks Must Die
• Blogging Basics: Comment Spam, Part I, Understanding Comments and Pingbacks
• Blogging Basics: Comment Spam, Part II, When Comments Go Wrong
• Blogging Basics: Comment Spam, Part III, Identifying Comment Spam

WordPress’s anti-spam tool, Akismet, does an excellent job of catching and filtering out spam so I don’t really need to see it at all. It also provides statistics about comments. This morning, while looking at these stats, I discovered that a full 98% of all comments posted on this blog are spam — or about 4,000 to 10,000 spam comments a month — leaving only 2% as legitimate comments (or “ham,” a term used by Akismet).

If this percentage is about the same on all blogs, it’s easy to see why so many bloggers elect to either turn the commenting feature off or require registration for commenting. (Note that registration doesn’t always help; some spambots can also register an account and then manual intervention is required to identify and delete those accounts.)

Comments are moderated here for two reasons:

• Aksimet doesn’t catch all spam. It misses, on average, about 10 spam comments a month.
• Akismet can’t identify abusive comments.

I have a zero tolerance approach to spam and abusive commenters and don’t want to see any of it on this blog. So I manually review all the comments that Akismet approves before allowing them to appear on this blog.

(If you believe that deleting comments is censorship or somehow violates your freedom of speech, read this and this.)

Personally, I’d like to see a higher percentage (and number) of legitimate comments on this blog. I like when good conversations get going among readers. I can think of two posts offhand where reader comments have added real value to what I’ve written: “The Helicopter Job Market” and “Why Groupon is Bad for Business…and Consumers.” I write from experience and my experiences are limited. When readers share their own thoughts based on their experiences, they provide more information for other readers to draw upon. They help round out a discussion. And as long as they don’t get rude or abusive to me or other commenters — or are obviously commenting to promote their own product or service (i.e., spamming) — I don’t care if they disagree. Intelligent, civil debate based on facts is encouraged.

But while comment spam is obviously a serious problem for all bloggers that allow comments on their blogs, I have it well under control here.