Even with BlogPulse is tracking 12 million blogs, the worldwide number is still much larger. I worry a bit that we are trying to estimate the number of angels that can dance on the head of a pin and that measuring size is not the metric we should be using. I do believe that influence is more important. I want to know the influence on music and dance the angels on the pin have, not how many were seen dancing.
That being said have come on some additional figures for size of blogosphere worldwide. Duncan Riley, using an interesting build-up method of estimation, has suggested that the worldwide size is closer to 60 million than the 12 million posted by BlogPulse. This still begs the questions: How many are spam blogs? How many are active?
Prefer the approach taken by the very interesting wiki on SocialText that gives insights into the European blogosphere on a country-by-country basis. Living in the US we tend to be too US-centric, particularly when talking about technology adoption. It is a sort of provinicialism, so sites like this wiki really give a broader view. I sure wish there was one for South and Central America.