Blog topics are inevitably dominated by just a few (a half dozen or so) blogs, for a simple reason: comments. People want to read blogs, but they also want a community, and in any one arena the community will gravitate to the place where others are already gathering.

When a topic is new, the first few bloggers form the community. Latecomers have to either be famous already (like Dawkins) or must be exceptionally good, or exceptionally outrageous (PZ is both of these). A blogger who might have attracted a large readership in the "early growth" days of a topic will be mostly ignored if he comes to the party late.

I've seen this in other areas besides blogging. In the early stages of a business (say online bookselling) you'll find hundreds of competitors. In a short time, most of them are gone. After that, it's almost impossible for newcomers to displace existing entities unless there's some game-changing event (like internet booksellers displacing brick-and-mortar booksellers).

The exact same thing happens in the blogosphere. But here, the commodity isn't goods, it's community. The blog with the largest community of participants attracts more participants.

In any ecosphere there is only room for a few species in any one niche. The first ones there fill the ecological niche, and latecomers have nearly-impossible task trying to displace them.

At the risk of sounding self serving, I devoted an entire chapter of The Religion Virus to the biological basis for this phenomenon. Humans, unlike most other animals, pass most of the information from generation to generation via language (memes) rather than genetically. In order to make this process reliable, our brains are programmed to soak up fantastic amounts of information (and to trust it) when we're young, and then to "freeze" it so that it can be passed reliably to the next generation. This memetic/genetic combination explains why children will believe almost anything, and why adults are so fixed in their beliefs. It's what makes us survive, and what makes us human. http://www.thereligionvirus.com.

Hey vjack, I wrote a blog today that's a bit of a reply to this one. I read this when you wrote it and have been pondering ever since, and all the news today made it the right day.

vjack -- I have to respectfully disagree with you on this one. Obama is a brilliant politician, one who understands the nuance of everything he says. He knows when to push and when to compromise. He knows when to throw a bone to an opponent. I believe that his statements regarding religion, and perhaps his entire religious life, is nothing more than a front, something that he knows he must do to be a successful president.

I don't take anything he says about God and religion very seriously. I believe it's just stuff he says to get credibility with religious voters. As someone else pointed out in this thread, he's not going to sway the evangelicals, but they're beyond reach anyway. But it does work on the middle-American centrist Protestant types.
My recent post The Scandal of Atheism

Christians and other theists often claim intolerance when in fact it is their own ignorance that it at fault. There's a difference between being intolerant and being right. If I'm well educated about a topic, and you insist that I'm being intolerant because I don't accept claims from you that I know to be wrong, who is at fault?

This is a great topic, one I wrote about recently on my blog: Science vs. Creationism: Arrogance or Truth?.
My recent post The Scandal of Atheism