Try reading: http://en.wikipedia.org/wiki/Meme

Lot's of answers to your "so fucking what?"

"In response to these criticisms, memeticists might argue that as their
discipline does not construe memes as "particulate" entities, they therefore
parallel indirectly the entirety of existing evolutionary taxonomy. (For
example, one would not preclude fish from the animal kingdom for their lack
of lungs.)
The author Evan Louis Sheehan, on the other hand, does attempt to rigorously
portray the cognitive representations of memes as "particulate" entities. He
defines them as patterns captured in cortical hierarchies, identical in
structure to what Jeff Hawkins proposes in his book On Intelligence (2004).
Each hierarchy expresses a complex pattern that the brain-owner has
automatically sensed and remembered, as a consequence of simple Hebbian
learning. "Sensed patterns" captured in these cortical hierarchies can
reflect anything from the shape of a tree to a commonly-performed pattern of
behavior that routinely propagates through mimicry. A cortical hierarchy
consists of a "molecular" entity, constructed from sub-hierarchies (as the
pattern of a tree comprises the sub-patterns of leaves, branches and a
trunk), which themselves ultimately comprise "atomic" entities - small,
patterned combinations of sensory elements. Memes thus take on a
"particulate" nature that allows their combination and re-combination in
various ways. Sheehan, in his book The Mocking Memes: A Basis for Automated
Intelligence builds a model of creative thinking around a rapidly-evolving
Darwinian process of combining and re-combining various causal memes, which
represent nothing more than remembered patterns of causality.

Sheehan describes a meme as any sort of pattern that serves as a template
for its own replication. He suggests that an understanding of memetics
requires a recognition of how such patterns get themselves automatically
translated - according to the strict laws of physics - from substrate to
substrate, as from patterns of light entering a human eye to patterns of
neural excitations in the retina of that eye, to the Hebbian development of
hierarchical patterns of neural connections in the cortex, and ultimately to
patterns of muscle contractions that serve to mimic the witnessed behaviors
of others.

Philosopher and cognitive scientist Daniel Dennett, in a debate with
theologian Alister McGrath, has responded to criticism regarding the lack of
rigor in the study of memetics by claiming that words and similar means of
spreading and holding ideas provide a clear model for the spread and storage
of memes. Sheehan suggests the automatic translation of patterns among
various substrates as critical to providing the means for spreading and
holding patterns of words and ideas. For example, we speak words through
vibrational patterns of the larynx, which get translated to pressure waves
in air, which then get translated to vibrations of a listener's ear drum,
which then get translated to waves of cochlear fluid inside the inner ear,
which then get translated to patterns of neural firings, which then get
translated to patterns of neural connections, thereby establishing a memory
of the spoken words in the listener's mind. Sheehan asserts that the
constant flitting of memetic patterns from one substrate to another makes
memes so difficult to pin down, as analogous to genes, but that the physical
processes that translate memetic patterns from substrate to substrate
exhibit an usually high level of fidelity.

According to Sheehan, "automatic translations of patterns from substrate to
substrate to substrate, and back again, provide looping pathways by which
patterns can iteratively replicate, mutate and evolve." Sheehan claims that
"many such looping pathways exist both within a single brain (to create an
intelligent mind) and among many brains (to create culture, language and
technology)."

Others suggest that many of the criticisms of memetic theory stem from
confusion over what the term "gene" refers to. In microbiology,
microbiologists see a "gene" as a cistron, a specific region of DNA. The
analogy between memes and genes, however, relates to an evolutionary
biologist's gene, an abstract replicatory unit of information. People[who?]
who think of a gene as an actual visible piece of DNA often criticise the
memetic analogy because of this. An example of such an "abstract replicatory
unit of information" might code for the color of one's hair or for the
length of a digit"