After mad comment spam, I've disabled anonymous commenting. Sorry.
The "word verification" thing that blogger offers is otherwise known as a CAPTCHA (an acronym for "completely automated public Turing test to tell computers and humans apart"). They're problematic because they're not actually Turing tests. They can be defeated by software which can figure out what the word is. Also, they can be defeated by motivated persons. For example, a script might grab my CAPTCHA image and post it to a pron site, telling a user there to de-scramble the CAPTCHA in exchange for access to naughty images.
In addition to not actually stopping spam, they also weed out real humans who have visual impairment and are thus a huge accessibility issue, to the point that it is surprising to me that they do not violate the Americans with Disabilities Act. I wouldn't be surprised to see them in an ADA-related lawsuit.
I'd invite comment on whether CAPTCHAs are better or worse than making you sign up for a blogger account, but ironically, those most likely to be in favor of the CAPTCHA solution can't actually comment. Blogger should take action to prevent the same IP address from hammering away too many times or too quickly.