Hyderabad, Andhra Pradesh arrived from google.co.in on "Not A Potted Plant: Doggie Personal Ads" by searching for personal ads blogspot.com.And there you have it. The spammer is in India, and did a search for every blogger or blogspot post that used the words "personal ads." Not particularly discriminating and he obviously didn't take the time to read what was in the post or even scrutinize the title. And this guy has a spambot that can somehow penetrate the word verification feature.
I wonder how much spam I'd get if I didn't bother to have that filter on the comments.