The following is another brain dump, but it may make more sense since parts of it have already been articulated elsewhere in semiunderstandable terms.
We may not all agree with reality as a fully social construction (solipism is a four letter word to the mathematically disinclined), but I think we all can agree that a certain amount of how we interpret events that are arguably 'real' is socially or intellectually influenced. Whether or not there's something 'out there', most of the time we interact primarily with our internal model, which may or may not correspond very well with the external (1:1) model, and we also use our model to make sense of the confusing and altogether super-ambiguous signals we get from our senses.
Now, priming is the term given to the way that our short term memory (especially the bits of it that we can't directly access) influence the interpretation of new signals often more so than long term memory. This makes sense. Our long term memory is contextual, since we have so much stuff in there that it would take forever to figure out that the shape on the ground is a poisonous snake if we have to sort through all the images recorded in that time when we flew a kite in the city and bumped our knee first (by the time we get to the category of 'forest animals' we're probably already bitten, and by the time we loop around to how to get to a hospital we're already half dead). The short term memory provides context, sort of like an index. But priming becomes increasingly complex and powerful at the level of multilayer symbolic interaction we get to with written and spoken languages that are more complex than what cats and dogs are capable of.
Priming affects not only our interpretation of signals, but also influences our output. 'Freudian slips' are only the most obvious examples. Many times, the signals are modified just enough to cause a change in word choice: the connotation will subtly change, though the denotation (and therefore the obvious meaning) will remain.
Now, this effect has a relatively small effect with a small group of relatively uncommunicative people. With a small group of highly communicative people, we get into what McLuhan calls the 'tribal system' -- think of it as being like the rumour mill in a small town, where a game of telephone stablizes into a semicoherent perception after a few iterations because of the incestuous interconnection of all nodes with comparatively few jumps: after hearing six variants of the same rumour, most people will decide to repeat only the version they like, likely back to the same people who have heard all the others, and a few versions will crystallize as canon due to repetition and popularity.
But on the tubes, we have an absurdly LARGE number of people with an extremely SMALL number of hops and minimal distortion of a given message (the human element of distortion is relegated to summaries, commentaries, and questionable mischaracterizations in an environment when the entirety of the original can be copypasted or linked to with minimal effort). This causes what McLuhan calls a 'global villiage' (which is actually such an overloaded term these days that most of the time when it's used it bears very little resemblance to what McLuhan meant by it) wherein a tribal system is scaled up massively while maintaining roughly the same level of interconnectivity and hops between nodes. This allows massive near-instantaneous propagation of all sorts of messages to all sorts of people, and in fact allows most of this communication to be bidirectional despite the large number of nodes, some of which are hubs or even combination maven-hubs. So, despite the fact that person X is on the other side of the world, they can still hear about person Y's actions of questionable taste/morality, and comment in a method that may reach person Y more or less intact. The rumour mill has become part of the underlying infrastructure of spaceship earth.
But, what of priming?
Priming was previously limited simply by the potential for bidirectional propagation and the modification (or, might I posit, processing) caused by the back-and-forth. With the internets, we currently have not only a global villiage with a massive number of people processing and communicating primed subtexts nearly instantaenously and nearly constantly, but we also have a semi-permanent log of a great deal of them.
And now for something completely different. (do you believe that?)
Carl Jung is credited with the concept of 'synchronicity', which is (very roughly) defined as meaningful coincidence. Both the word 'meaningful' and the word 'coincidence' are entirely relative to the point of view and level of abstraction one is working at, obviously, but it's a nice thing to build on. Jung, in fact, didn't come up with the idea, but he probably thought he did. In the movie Repo Man, synchronicity is called the 'plate of shrimp' effect.
The normal explanation for this is termed 'the law of very large numbers': in other words, no matter how uncorrelated with reality a bias is, given enough data one can cherry-pick pieces of evidence to convincingly impose a pattern. Cherry-picking data is called a stochastic process, and is the cornerstone of science and cognition, as well as being the cornerstone of defense for all forms of dogma (anti-evolutionism, dogmatic materialism, political propaganda, conspiracy theories, fundamentalist creationism, racism, and cultural elitism, to name a few). In theory, the major difference is that dogma cherry-picks things to flatter itself and defame other dogmas while science is supposed to cherry-pick things to flatter and defame everybody on and off in turns. Synchronicity is typically explained away as starting with a meaning and ignoring all coincidences that don't flatter it.
However, does that actually pan out? The 'meaning' in the synchronicity is rarely there before it is seen -- instead, the meaning is picked out because of a few strange coincidences, and once it is picked, the number of coincidences involved expand significantly.
A certain amount of this is going to be the law of very large numbers by itself. However, a certain amount is probably going to be due to other people's research on the *exact same meaning*. For a simple example, Burroghs started a journal of accidents involving the number twenty three, which spurred Robert Anton Wilson to do the same. Both authors dropped references to the number's 'meaning' in their books, and a certain amount of the following of 23-related coincidences is probably due to indirect references-to-references-to-references (Jim Carey's movie "The Number 23" is probably not directly inspired by Burroghs or RAW, despite the trailer referencing several things found in the works of both).
There is something that is called the "net of synchronicity" -- something that a follower of coincidences starts to notice, wherein (far more than even the law of very large numbers should probably explain) certain strange coincidences seem to be highly interrelated. For instance, Burroughs connected 23 with the name "Clark", while Wilson connected 23 with Aleister Crowley, the Sirius system, and the 1960s drug counterculture.
I suppose that in a way, the net of synchronicity is probably the collective product of the interchange of primings within a somewhat interconnected group of people interested in particular types of coincidences. Wilson got 23 from Burroughs, and picked up Crowley from a friend of a friend of Burroughs, and then got the Sirius association by juxtaposing the 23 element with the Crowley element, and a good number of his contacts during that time were associated with the 1960s counterculture. In the internet age, synchronicities can piggyback upon each other, and synchronicities can become self-fulfilling prophecies due to both direct and indirect influence (subconscious anxiety on a flight 13 can cause a pilot to panic and crash rather than think critically and pull off an emergency landing, changing a happy ending into a disaster, while meanwhile a movie producer may reference the number 13 simply in order to piggyback on the existing fears surrounding it). This can happen far faster and far more complexly than without it, and a lot of the early sources are still around and documented there. Time binding is becoming far more efficient.
One can probably argue (as I am wont to do) that in a way, through these layers of both conscious and subconscious communication and processing, we are becoming sort of a super-organism. Without the internet, we are sort of like a loose colony of cells, like slime mold (which is a colony of single-celled organisms that manage to work together well enough to pass for a single organism occasionally but can easily break into its component parts, and then reassemble). With the internet, we are a much larger organism, wherein the cells (us human beans) are highly interconnected by high speed broadband axions, and wherein short term stable pattern in a continuously evolving conversation between huge numbers of nodes. This synchronicity net can both consciously and subconsciously influence a large number of people, which of course will influence their actions to some extent. Given enough time, a stable self-organizing pattern of instructions will occur, and a number of actions that are seemingly unrelated will cause a 'perfect storm' situation for a given action, which will then happen. This action cannot really be said to be the choice of any given person. Instead, this action (being quite deliberate in retrospect) is the emergent decision of all of humanity as a single entity, with no hierarchical structure being involved in the actual decision. This action in of itself may become the cornerstone of a totally new synchronicity net.
So, tl;dr: wierd conspiracy theories, wiki defacement, 4chan, twitter, and facebook are the unwitting central and peripheral nervous system for a being the size of the earth and exponetially more intelligent than any given human on the network.