The word meme was originally coined by Richard Dawkins, an evolutionary biologist, in his book The Selfish Gene, which laid out the argument that individual genes could be treated as being affected by natural selection. The term is a new version on the observation that "ideas" spread like a contagion. As such there is an entire academic study of memes which takes the original analogy seriously.
As used on the Internet the term has a related, but different meaning. Since in the digital environment, fragments of information really do have an exact reduction - unlike "ideas" between people which do not - a "meme" in Internet terms is any fragment which is easily memorable, easily recallable, and which drives out other competing frames of reference. A successful meme is characterized by people's willingness to send the meme on to other people, so that it will spread. (See viral marketing, message). Thus the important characteristics of a meme are: memorable, recallable, spreadable, applicable, credible and terminal.
Memorable, recallable and spreadable are all relatively obvious. Credibility is somewhat more elusive: some memes are not credible if actually stated, where they can be refuted, but the meme itself must be credible when used. For example "Saddam bin Laden" is not credible, but it can be used credibly. Applicablity is the property of a meme to be invoked in a wide variety of circumstances, "Dissent endangers the troops" is one example: almost any line of argument can be stopped if it can be troped (turned, redirected) to damage the morale of the troops. Terminality is the property of a meme that it ends discussion, thought or debate. A successful meme crowds out other interpretations, even obvious ones, from the listener's mind.
Memes are generally described in their most generic form, for example "Saddam bin Laden" is a description for the meme that Saddam was related to the 9/11 attacks in some way. As can be seen from this example, memes do not rely on evidence, or even direct assertion, but instead are meant to evoke a particular image.
memetic code versus alleles
The word meme is often applied to two related, but separate, entities. One is the actual quotation or fragment which is spread, or its variations, the raw "memetic" code and its "alleles". The other is the underlying tropic meme - for example "Democrats are soft on defense" is an example. Sometimes called a theme by political commentators, the usage of meme for both is likely to continue. In linguistic theory these are often called frames, and asserting and establishing a new meme is called reframing the debate. (See George Lakoff, paradigm, and the process of deep framing itself)
relation to terms and positions
At dkosopedia itself a careful differentation is made between a genuinely held position that is argued rationally, and a suggestive or assuming term that is used to assume that the labelling or distinction that it makes is valid. In some cases, a term is meant to evoke an idea in on group, while maintaining plausible deniability to others, as in the use of Code Words. For instance the term:evacuee and term:illegal combatant have specific legal and political purposes that you accept if you use those terms at all. Likewise, the position:climate change caused Hurricane Katrina can be, and is, rationally argued. A meme however discourages examination of the underlying assumption, and any rational debate tends to acknowledge premises of the meme's issue statement, which is not neutral at all. The question of "whether" Saddam and bin Laden are or were in league, which is not alleged as a position by any serious analyst, is not worth debating except insofar as the memetic term "Saddam bin Laden" raises it. Saying that a Democratic or Progressive proposal is Socialist (that is, Communist, not Social Democratic) resonates with the Republican base (where it appears to mean some combination of pro-minority, anti-greed, and anti-Christian Right), but is meaningless to anyone else.
Because any assertion or concept can be a meme, it is futile to label them in a separate meme namespace: this would only cause fights about what was there and what was not. If something is a position that can and should be argued, or a term that has premises amenable to investigation, then it is "more than just a meme" and can be analyzed. For example, Global Warming is a concept and a position among scientists and those who follow their work, and a meme among Global Warming deniers who reject not only the science but the scientific method.
Partisan political discourse often works by asserting memes which end discussion, or stop thinking, while examination of terms and of positions does exactly the opposite: it opens examination of premises, facts, methods of arriving at truth, and what should be done about them.
relation to tropes and factoids
Related to memes are tropes and factoids. The word "trope" means "turn", and it is from the ancient Greek, where Homer describes Odysseus as of "many turnings". The word "tropic" comes from "trope" because the tropic is where the sun "turns" back on its course from north to south, or south to north. A trope is a turn which recalls the original. This means that puns are one example of a trope, but plot "twists" are as well. A trope in critical theory describes how different images or incidents are tied together. Most memes rely on a "trope" of discourse, a common pattern of turning. See, for example, the Web site TV Tropes.
One example of a trope is The Enemy of My Enemy is My Friend, like the Soviet Union during World War II. This is used in reverse to connect Saddam Hussein and Al Qaeda, since each is the enemy of the other's enemy, the US. This is combined with the meme "Iraq is the central front in the War on Terrorism", where a second trope is The War on X, which leads to the idea of "fronts" in the war. Connecting Saddam to Osama works by the chain, "Osama is the enemy in the War on Terrorism, Iraq is the central front on the war on terrorism, therefore Iraq is related to Osama".
The word factoid is in the state of flux. It's original meaning, now overshadowed by its variation, is according to Merriam Webster, "an invented fact believed to be true because of its appearance in print." An example would be claims that Al Gore said he "invented" the internet, when in fact he said that he "took the initiative in creating the Internet" with a funding bill. One of the best known factoids is the story of George Washington and the cherry tree, invented by Parson Weems in his Washington biography.Another contributor gave this description, which I do not believe is an accurate definition of the word, "factoid." but should remain on this site since it is what people think the word means:
It is an observable without a frame of reference, whether an anecdote, a statistic, or an historical event. Factoids are given context by spinning them, that is, applying a trope to the factoid to relate it to a meme. An example is "GDP grew at 4.5% in the First Quarter of 2004". This could be spun as "we are no longer in recession with such good GDP growth", it could also be spun as "almost all of that growth was government or consumer borrowing, therefore the economy is still frail without stimulus". The factoid means nothing by itself.
One example of a meme at work is the meme "Saddam is a liar", which was backed up by factoids (in this second sense) of his being uncooperative in the extreme to weapons inspections. This was used to spin factoids (in the original sense, through constant repetition in the media) of possible weapons, to imply that they represented the tip of a very large iceberg.
memes stop thinking
Political discourse works by asserting memes which end discussion, or stop thinking. They are buttressed by, or countered by, other memes and factoids, and held together by tropes.
insertion and risks of insertion
Crucial to the use of memes in political discourse is their insertion. Inserting a meme is an attempt to have other people repeat the meme and use it.
A meme is said to be "insertable" when it is in a form which will be readily remembered and repeated. A bumper-sticker spreads a meme by making people want to put it on their vehicle, an email message spreads when people forward it.
Political operatives have a variety of means to attempt insertion from "trial balloons" through political advertising, blast faxes and some even provide video to news organizations to run as part of their broadcasts.
However, insertion does not always insert the meme that an operative intended, for example, the "Mission Accomplished" banner was an attempt to insert the idea that victory had been achieved in Iraq, but is now a factoid for Rovian manipulation, and part of the "Republicans will do anything to spin the public" meme.
There is extensive critical theory associated with post-modernism on tropes, memes and factoids, but, as yet, no cohesive theory has emerged for them.
A forum where this is extensively debated is openpolitics.ca where there is an effort to catalogue what is called postmodern politics and catalogue global and continental and Canadian issues rationally to allow position taking on them. This forum excels in the study of meme insertion, and has made some deliberate moves to attract known trolls who are expert at this insertion. For a good overview of the type of discourse and terminology about discourse that this entails, see the list of notices and categories that apply to pages, the twelve levers of Donella Meadows that are applied to design decisions, and the control verb, commit verb and list of process terms that have evolved. The effort spun off from an earlier one called Living Platform which was used by some Canadian Green Parties to debate policy, and is spreading to the simpol.org global policy system.
Another forum where theory is applied, rather than debated, is sourcewatch.org where the originators of public relations materials are closely examined. This is mostly focused on US issues and so will be of more interest.
(see also MemeTank)