There has been much speculation out and about in the comments at Sb and elsewhere that a [sigificant, distressing, salient...you name it] number of blogs have departed Scienceblogs this year. Some of the bloggers in question have left signoff messages or commented elsewhere to the effect that they are leaving in a huff, which fuels this speculation.
Being a relative n00b around these parts I was curious about the ebb and flow of blogs on ScienceBlogs over the years since launch. Have we witnessed an unusual flurry of departures in the past couple of months? Let's review the data*, shall we?
Departures from Scienceblogs.com by year
Frink Tank (no link trail that I can find but see this)
No Se Nada (Jan)
Smooth Pebbles (May)
Dr. Charles (Jun)
Integrity of Science (Aug)
Galactic Interactions (Dec)
The Cheerful Oncologist (Jan)
Omni Brain and Retrospectacle fused into Of Two Minds (Mar; but S. Batts essentially quit by the end of 2008)
The Voltage Gate (Jun)
The Loom (Jul)
Mixing Memory (Aug)
Deep Sea News (Sep)
Science To Life (Oct)
Angry Toxicologist (Dec)
Chaotic Utopia (Jan)
The Intersection (Mar)
See Jane Compute (May)
Pure Pedantry (May)**
Stranger Fruit (May)
Evolving Thoughts (May)
Doctor Joan Bushwell's Chimpanzee Refuge (May)
Interesting. A glance over the linked final-posts will give you a flavor of the diversity of (overt) reasons for departure. It is harder to determine how many active blogs there were at each time of departure so it is tricky to estimate the percent departing. It looks, however, as if there were about 53 blogs by the end of 2006 (the launch year) and the current front page claims 70. I have nothing to go on with respect to the natural lifespan of a given blog but certainly some of the final posts will inform on that topic.
*I have probably missed several departed blogs, hopefully old-timer Sb'sters will clue me in to any omissions.
h/t: I have been able to short-cut the data collection by relying on the memories or prior posts of various Sb bloggers.
Additions, Corrections, etc after initial post: Neurontic and Frink Tank (h/t Bora)
**As Scicurious notes, the primary blogger at Pure Pedantry moved to Neurotopia. I think it should still be included as a closed blog, albeit with asterisk.