Blogs are a great source for commentary & instruction as well as helpful dialogue. There are dozens upon dozens of blogs related to R & statistical computing, the quality varies pretty widely. The blogs listed here are both well written & regularly updated.
R-bloggers - This is a mashup of a number of quality R blogs. They vet for quality, so this is good stuff, and because so many authors are contributing it's updated daily. This should be on your reading list.
Revolution Analytics Blog - Revolution Analytics is a company that has contributed quite a bit to the development of R. This blog is updated several times each month, usually with tips on how to handle big data or interesting commentary. They've had a handful of great interviews with prominent data scientists as well.
R-statistics - Written by statistics graduate student Tal Galili, this blog is update a little less than once each month and is a collection of practical tips for computing with R. Galilil always includes code samples so his posts are informative & interesting.
R Data Mining Blog - R Data Mining is the project of Yanchang Zhao, Ph.D. This blog primarily focuses on data mining techniques, so you'll see posts related to Excel & Python as well, but most are on R. All of the content here is high quality, Dr. Zhao knows his stuff.
An honorable mention goes to Simply Statistics. While not directly tied to R, this is a very well written blog about the practical application of statistics. Common themes are big data, analysis of the statistics found in popular news stories & more. This is a great blog that should be on your reading list.