It's a useful analogy, helpful for a basic understanding of both biological evolution and culture. It powerfully conveys the truism that ideas can't survive without winning new minds. It demonstrates that the basic process of natural selection is just an abstract principle that can apply to many things that replicate.
But I think people are too enamored with the analogy (Daniel Dennett in particular). Does it really work as a theory of social interaction? The source of the idea also rings skeptical bells. Just as I don't expect new revolutionary physics to first be published in a book written by an engineer and marketed to popular audiences, I don't expect a new revolutionary theory of social science to first be published in a popular science book about evolutionary biology written by an evolutionary biologist.
When all you have is a hammer, everything looks like a nail. And perhaps, when you're an evolutionary biologist, everything looks like natural selection. And since I'm a skeptical blogger, everything looks to me like a claim to be questioned.
I can't really speak to the expert criticisms of meme theory (though a cursory glance at Wikipedia indicates that there are many), but there's at least one flaw in the meme/gene analogy that jumps out at me. What is the origin of a meme? While ideas aren't created in a vacuum, it's difficult to describe them as "descendants" of other ideas. Many ideas just have no traceable source, or they look completely different from their source. As far as biological evolution is concerned, it's extremely important that the offspring look at least a little like their parents. The traits that improve survivability need to be consistently heritable for evolution to go anywhere.
And many ideas come from more than one source. There's hardly any speciation of memes, they all just mix and cross-hybridize. Even in religion (a common example of a meme), syncretism is absolutely commonplace. Imagine if this were the case in evolutionary biology, we'd have crocodiles reproducing with ducks!
I know I've written a lot of posts expressing idiosyncratic disagreements with Dawkins, Harris, and other prominent atheists. But that's not even what's going on here. Based on things I've heard Dawkins say, I fully agree with him. Take this interview from 2004:
When Dawkins introduced the meme concept a couple of decades ago, hopes were raised that the evolution of culture, or even of the human mind, might be explained as a sort of Darwinian competition among memes. But little has come of this project, even if the word "meme" does continue to get tossed around quite a bit by pretentious intellectuals. I asked Dawkins if he had cooled on the meme idea over the years.Well, yeah! Memetic evolution is a powerful tool to explain evolutionary biology to popular audiences. It's not actually meant to contribute to the study of human culture. I mean, isn't that what the social sciences are for? I know we all like to hate on the squishy social sciences, but to take memetic evolution seriously does not strike me as an improvement.
"My enthusiasm for it was never, ever as a contribution to the study of human culture," he said. "It was always intended to be a way of dramatizing the idea that a Darwinian replicator doesn't have to be a gene. It can be a computer virus. Or a meme. The point is that a good replicator is just a replicator that spreads, regardless of its material form."