This is the last article from the series. I've received a bogus DMCA complaint, filed a counter claim, which was rejected by Google. Then I've contacted a member of the band who sent the DMCA complaint. He admitted that it was sent by mistake and promised to contact Google.
Today I got a message from Google which informed me that "We received an email from the complainant officially rescinding their complaint against your blog. We have reinstated your content located at http://googlesystem.blogspot.com/2008/02/lyrics-for-youtube-music-videos.html. The post in question has been reverted to draft. Please log into your blog and republish at your convenience."
The post is back online. I know it's obsolete, but at least it hasn't been removed by a DMCA complaint sent by mistake.
If you ever receive a similar DMCA notice, contact the owner of the site or his team and explain your issue. You'll probably find a contact form, an email address, a Facebook/Twitter/Google+ page. If not, a WHOIS lookup should help.
Thanks to everyone who helped me fix this issue and special thanks to James Trimble from the band Inspection 12 and +Thomas P. TechDirt has recently posted an article about this and its conclusion is that "the real culprit is the DMCA itself, which is constantly pushing companies like Google in this regrettable direction, and makes it all too easy for rightsholders like Inspection 12 to abuse the law".