A blogosphere is a term used to describe all blogs which are grouped together under one “umbrella” as a blogging network (has many blogs and many contributors).
I read the Canadian blogosphere. The name indicates to me it would cover all things Canadian but was mainly political. Within the Canadian blogosphere were smaller groups of blogs based on political views, party affiliations & physical location for example Paul Martin's blog.
Blogs were used to both defend and attack politicians by journalists like Rick Mercer and others.
I suppose these could be classed as “satellite” blogging networks they have their own smaller groups but are still part of the larger blogosphere.
The largest “satellite” group was the “Blogging Tories” (link)which had 300 blogs & 3,000 readers.
A poll taken in 2005 stated that 42% of Canadians had read a blog in the previous 3 months. That figure, I think, would have doubled by now. Blogging networks are very popular and a convenient way to keep up-to-date with issues or topics you are interested in.