Wired News discusses ambiguous or unavailable installed-base figures for blogs. Surprisingly, they spell blogosphere with a hyphen as well, following Newsweek style? Meanwhile, the VC-oriented world looks elsewhere:
Industry research powerhouses are likely to stay away from the blog-osphere until it reaches profitability. Gartner, Neilsen\//NetRatings, Forrester Research and International Data Corporation don’t have a single analyst involved in gathering blogging data.