Yesterday there was an interesting ecco seminary about memetics by Øyvind Vada. In contract the the explanation on the wikipedia, that mostly refers to Dawkins (1976) who explains it as "unit of cultural inheritance", Vada goes back to earlier work like the idea of "units for cultural transmission" (Semon, 1904) and "a memory trace" (Maeterlinck 1927).
To explain memetics I guess a application can bring most clarity. As Vada pointed out, it is quite hard to work on a topic if the topic is not clarified first. It can be seen as the force to spread information or by metaphor: a meme is for cultural system what a gene is for living systems. Memetics is an interesting topic in evolution theory. Memetics becomes confusing when looked at the overlaps with social science, telecommunication or semiotics. Francis pointed out it helps when we take the position of the meme itself. The two examples that clarified the topic the most for me is by utilization of memetics. One example is viral marketing. It illustrate the spreading force. The other is a suicide bomber, it illustrates Francis point of view. The fitness of a suicide bomber is only rational form the view point of a meme: nor evolutionary nor social does it fit.
Vada's question was if memetic is a science yet. This brings us to the fact that memetics is in need of novel fact, its epistemic basis is to narrow. It brings us into the field of science studies (my piece of cake). Form the field it is understood that theory and practice are co-evolving and will mutually reinforce each, other (in other words the theory and practice are bootstrapped). Like the two applications did make it more understandable (I hope also for you). It would be nice to try out an experiment to increase the knowledge base by expanding "the opposite" category. My two cents are that the theory will become more clear only after enough applications exist.