This post in progress...
Here are some thoughts on memetics as construed by Blackmore. The book has 18 short chapters along with a preface and a foreword by Richard Dawkins, so I do not comment on everything. Just some notes as I am reading.
I am mostly sympathetic with the concept of memes, but I retain some skepticism about the ways that the concept may or may not be applicable to human evolution, either cultural or biological. My basic thought is that it serves us little to consider the ways that memes may be structured to maximize their own dissemination and retention, but it is potentially very applicable to consider the ways that human minds may be adapted to retain or spread certain kinds of information. Thus, if a meme is a behavioral analog of a gene, then what I think is interesting is whatever would be the behavioral analog of developmental genetics--the biological evolution of an unfolding genetic program that creates a mind via interaction with a cultural environment. To what extent are minds genetically inherited (i.e. culture- or meme-independent) and to what extent are they culture- or meme-constructed?
This question may seem trite, in that it amounts to a restatement of the nature vs. nurture question. But there really isn't a way to address the biological evolution of human cultural capacities without grappling with it. If cultural capacities are largely bootstrapped by cultural learning in a substrate-neutral context, then the particular genetics underlying mind construction might matter relatively little in the emergence of modern human behaviors. In contrast, if most interesting human behaviors are culture-independent or universal, then we require explanations for them that explain their commonality in the face of cultural variation. One possibility is that culture is constrained, either logically or biologically. Another is that human cultural capacities are strongly genetically determined in some respects. It is very likely that most human capacities are in between, and in fact that the extent to which they are facilitated by particular genotypes may vary from person to person.
My thoughts also boil down to a question of the kind of variation that we consider to be interesting--culturally variable or culturally universal? For me, the question of memetics is whether memes are phenomena that have importance to the construction of minds from the perspective of biological evolution. I am reading the book with that question in mind. It could be the case that the behavioral choices that underlie survival and reproduction are highly influenced by the ease with which particular information structures may be transmitted and retained by individuals. In that case, the neurobiology that enables the replication of memes may be a relevant way to frame the issue of biological evolution. But it may be the case that the interesting ways in which memes are transmitted and maintained have no special relevance to survival and reproduction. Even so, memes might be very interesting in some intellectual pursuits, such as the analysis of changing hemlines or urban myths, but they would not constitute an interesting way to construct a theory of the evolution of cultural capacities. Again, I suspect the truth is somewhere in between these extremes, but if so there might remain some way other than memetics to make a productive theory of the origins and evolution of culture.
A few notes before starting. Here I use several terms in a way that is meant to avoid confusing myself. For this reason, they may seem idiosyncratic, but hey, it's my weblog. I use cultural evolution to refer to changes in culture over time. This has no necessary implications for the utility of cultural categories or their value to individuals, but those may be factors that affect the pattern of cultural evolution, certainly. My main interest is in the biological evolution of those mental functions that allow cultural behavior in humans and other animals. For this, I refer to the evolution of cultural capacities. With respect to the study of "capacities," it goes without saying that no two individuals are likely to be identical in performance, and in practice their manifestations of surface behaviors are likely to be very different. From a biological perspective--especially as applied to survival and reproduction--differences in performance have to be considered in a statistical framework. That is to say, do two individuals have the same likelihood of exhibiting particular behaviors in particular contexts? Could they both be expected to learn the same information given the same inputs? These are questions that focus on capacities rather than performance, and they illustrate that selection on mental capacities may occur as a function of statistical relations between minds and behavior, even if there may be no sense in which the structure of minds can be said to determine behavior.
Dawkins originated the meme concept in his 1976 book The Selfish Gene, and as such he is certainly the best qualified to provide an introduction and contextualization of this book.