(Note: Links are deliberately not clickable, we don't want to give the Spammers pagerank)
Blogger has a pretty significant amount of protection against comment spam. They have to, because comment spam degrades the blog ecosystem. On this personal blog, I've just gotten comment spam like this:
I have to say that I love this article. I have searched for many weeks to find an article about this topic. This blog has been so simple and has a lot more features than other blog articles. The layout and design is great. I will continue to come back here for every articles. Thanks.........
Eva Maryam (a link to kitchencabinets-online.SPAMblogspot.com)
www.jetblue-airlines.SPAMblogspot.com (another clickable link)
Both blogs are simply full of automated-feed content from www.SPAMgetmyarticles.com, a company which gives free articles for posting on websites, probably mostly spamblogs, to make them seem legitimate. And the rest of the blog is a pile of Google adds.
It cost the spammer roughly $.01 to post that single bit of comment spam!
I have "Word Verification", aka the comment CAPTCHA, turned on. This means the spammer either had to invest a lot of effort in building or buying an automated tool, did it manually herself, or outsourced the CAPTCHA solving to a human, such as the Amazon Mechanical Turk, a porn-for-CAPTCHA service, or a Chinese Turing farm. But in any case, all the alternatives effectively cost real money. A CAPTCHA can protect something valued at less that <$.01 or so, but anytime the value is >$.01, CAPTCHAs are useless because you can always just hire people.
I should consider it a complement that the spammer would spend $.01 to post an advertisement on my inconsequential blog. And thus I can see how the spam blogs make money: there are a lot of adds spewed out on that page and it costs nothing to set up. Just a single click might make the spam-blogger $.10 or $1.00 or even more.
And they make enough money to make solving CAPTCHAs worth it, which means blog spam is far more valuable than email spam. An interesting result, and not good for the viability of blogs when comment spam on a random, nearly unread blog is actually worth money to the spammers.
The best counter is probably to attack the add-blogs themselves. All of the content in the spam blog itself doesn't cost the spammer, but by not paying for hosting the Spam blog, they are vulnerable. If Google actually responds to my flagging of the spam blogs which post comment spam, this would disrupt the spam-blog ecology.
But we will see in the future whether this happens, whether Google decides it benefits more from add impressions through spam blogs or is hurt due to the disruption of the blog comments system. I hope for the latter, as manually removing such spam costs me more that $.01 in my time.
The interesting thing is Get My Article's business model. Its free to use the content, but submitting the content requires paying $20/month, and requires actually creating semi-real content! So why are people paying good money to have their legitimate text articles (albeit complete with links) on people's spam-blogs?