Title: Nephrology Blogosphere: An Analysis of Productivity, Longevity, and Consistency
Joel Topf Medicine, St John Hospital and Medical Center, Detroit, MI. 
Background: Blogs are web sites with multiple discrete chronologic entries (typically displayed with the most recent at the top and older entries displayed below). There are numerous inexpensive and easy to use tools that allow blogs to be published with little technical friction. There are dozens of blogs that focus on nephrology and nephrology education; while most are still producing content some have ceased publishing. Little is known about the size, productivity, and lifespan of nephrology focused blogs.

Methods: Every nephrology blog written in English was assessed for productivity, longevity and inconsistency. Productivity was measured by the number of posts per month. Longevity was measured by duration of publication from first post to either the final post or through May 2013 for active blogs. Inconsistency was defined as the number of months without any posts.

Results: From March 2005 through May 2013 we found 30 nephrology blogs that published 10,198 posts. Twenty blogs were still publishing as of May 2013. Mean productivity was 339.9 (95% CI 175.2-504.7) posts per blog or 9.0 posts per month (95% CI 5.7-12.4). Longevity ranged from 1 to 73 months with a mean duration of 31.2 months (95% CI 24.1-38.3). Inconsistency was not common, with a mean of 4.6 months without posts per blog (95% CI 1.8-7.5). 11 blogs never missed a month, and 4 only missed 1 month.

Regression versus time show that most blogs lose productivity over time. Of the 25 blogs with at least 6 months of publication, 15 (60%) had a decreasing productivity over time (p<0.05) versus only 1 (4%) with a increasing productivity, 9 (36%) showed no association between time and productivity (p>0.05). Despite decreasing productivity in most individual blogs, the entire nephrology blogosphere showed a significant increase in the number of posts per month, R^2 0.38 p<0.001, slope 1.17.

There was no association between inconsistency and termination of the blog (R=0.18, p-0.35).

Conclusions: Blogging is a new means for distributing nephrology education. The number of blogs is increasing. Most blogs have decreased productivity over time however the nephrology blogosphere in total is growing both in number of voices and monthly posts.