The blogosphere was hit by a blogspot.com splogbomb. Someone did the inevitable and wrote a script that created blog after blog and post after post.
I'm not talking 100 blogs with a 100 posts each. I'm talking what could easily turn into 10s of THOUSANDS of blogs pinging out millions of posts !
So please Google. Add a challenge system. Dump the flag you tried. It was a nice try, but doesn't get the job done. Its not an imposition to ask a blog poster to confirm their post with a link inside an email, or a word confirmation. It may not eradicate the problem, but it will improve the quality of information available in the blogosphere considerably.