Will Richardson quotes the results of a recent study at Technorati , which shows that perhaps 80,000 blogs are created a day. The Technorati report lists the increase in blogging sites, blogging tools, drift to mobile blogs etc. They just look at those blogs that register with Tecnorati (and remove those that appear to be spam only)
One “good” finding though is that some 55% of blogs are seen as active, with 13% updated weekly.
My own feeling is that I thought that it would have been lower than that, but perhaps that’s also a reflection of those who register with Tecnorati.