One of the frustrations of dealing with the word verification aka captcha, when a blog is falsely identified as a spam blog, is that only the person that owns the falsely accused blog can truly experience the problem. Those of us who try to help cannot, in any way, reproduce the problem.
Any other problem - whether a dropped sidebar, or maybe a squashed navbar, or even an improperly centered snippet of code, we can either reproduce in a test blog, or examine in the blog in question. By carefully examining the blog, or the page source, we can sometimes see what's wrong, or at least see enough of a clue to tell the blog owner what to try next. Or maybe we can get an idea what additional diagnostics might be useful.
The problem of an inoperative captcha - where either the captcha text window shows up blank, or where the blog owner carefully types the answer, hits Enter, and nothing happens - sound to me like another problem with cookies or scripts. If this is being seen more frequently recently, it's possibly just another symptom of over diligent security measures.
My suggestion? Let's see if clearing cache and cookies has any effect here.
>> (Edit 2007/6/5): We have new word on the situation, including actual documentation.
An Important Update
If you did not use a Blogger / Google account when you Followed this blog, years ago, you are probably not Following now . During the past...