I am running the Daily Delusions blog which consists of the main blog plus 2 separate blogs used for links and smaller snippets. This blog has a second author: my boy-friend.
I am also running a blog for one of my roleplaying campaigns which has a total of 6 authors. The others are for the players but only one of them has ever posted an entry.
Thirdly I am running a third blog for another rpg campaign of ours. This blog has 8 authors half of which are active. Of course the 6 and 8 authors of the two rpg blogs overlap.
Lastly I have been experimenting with new blogs all the time: I used to have a recipe blog, a blog for game masters, a blog as a diary and a blog for this and that. I even had a blog to develop an rpg character concept and I have been thinking of setting up a birthday blog for myself this year as a “prequel” to the inevitable party.
All in all my guess is that I have 2 active blogs and 4 active authors. But I really have 5 blogs and 10 authors on my mt installation.