The post yesterday where I reflect David Dobb's departure from ScienceBlogs made me reconsider why I blog. There are many sorts of blogs out there. Some, like The Daily Kos, are involved in affecting social and political change. Others are basically notepads for personal hobbies. Many blogs are run by writers who have a "beat" and try out ideas and supplement their print content on the web. And so on. So why do I blog? To learn. I've made this pretty implicitly clear before, but I thought I would make it totally clear. This doesn't mean that other people can't learn from me, but, fundamentally that is a byproduct of the ultimate reason I blog. From example, right now I am working on a bottom up reductionistic derivation of the breeder's equation based upon the treatment in The Principles of Population Genetics. Now, I suppose people may learn something from this, and I hope they do. I try not to be so obscure as to be unintelligible. But, in the process of reprocessing it for public consumption I refine and clarify my own understanding of concepts!. And, quite often there are pointers in comments to further reading and exploration of the topics I bring up. This doesn't mean that in every instance an exchange between myself & a reader has to result in a net accumulation of knowledge or conceptual clarity on my part, I'm not totally selfish. But, I certainly wouldn't blog if over the long haul I felt that I wasn't getting anything out of the process and dialog. This is why I am such a fundamentalist about having a high quality, if low quantity, comment stream (I try to achieve this by a mixture of deletions and abusive treatment to set examples). The world is full of drivel. I can go to the nearest coffee shop and listen as people who know nothing about everything display their ignorance without any self-consciousness. I don't blog to replicate that sort of "third place" online.