Keteria is, admittedly, not a name by which this world's creators refer to it—nor, as far as I know, is it a name by which anyone has ever referred to it before. But the world didn't have a name, and I had to call it something—as with most alternate Earths, this can be presumed to be a name just used for convenience in the Wongery and not actually in use by the world's inhabitants.

The world of Keteria (as I'm going to go ahead and call it) originated when a contributor going by the name of Moto42 on the 4chan paranormal imageboard /x/ ran across a picture of a wooden statue by Japanese artist Izumi Kato, and decided it was unsettling enough to be the basis for a bit of eerie flash fiction. He therefore posted the image to /x/ with a few hundred words referring to the statue as "SCP-173" and describing it as "animate and extremely hostile". According to his portrayal, SCP-173 was unable to move when not being directly observed, but when unobserved was capable of very rapid movement, and killed anyone nearby by strangulation or by snapping their necks.

(Yes, this is a very similar idea to the Weeping Angels from Doctor Who. SCP-173, however, was first. (Though it's unlikely that either Steven Moffat (the writer of "Blink", the episode in which the Angels first appeared), or Russell T Davies (the Doctor Who showrunner at the time) had ever heard of SCP-173; the similarity is almost certainly paranoematic. And, of course, the Boos from Super Mario Bros. 3 also work similarly and predate either of them, but, again, I'm inclined to chalk this up to coincidence.))

More significant in the long run than the details of the description of SCP-173 was its format: the text was presented as some sort of official report from an unnamed organization, which covered aside from the description an "Object Class" ("Euclid") and "Special Containment Procedures", which included the injunction that those in the object's container "are instructed to alert one another before blinking." Of course, if there was an SCP-173, it was logical to conclude that there were, or at least had been, at least 172 other similar items categorized—and other contributors decided to try to detail them. The format of the SCP-173 writeup was to become a template to be followed by the hundreds of SCP articles that succeeded it.

(A note on SCP-173, however. An amazing number of people have suggested outsmarting SCP-173 by closing only one eye at a time instead of blinking, and patted themselves on the back for having had this brilliant idea that clearly nobody else had ever been clever enough to think of. Apparently none of these people ever thought to try this. It can't be done. That is, you can certainly concentrate on closing your eyes alternately, but that won't stop you from involuntarily blinking after a while anyway. The same goes, incidentally, for "solutions" like water-filled goggles. It's not as if your body monitors your eyes' moisture level and blinks only when they're overly dry; that's not how blinking works, people.)

Over time, an elaborate lore developed regarding the "SCP Foundation", the organization that catalogs and curates all these SCPs. "SCP" itself became an acronym for "Secure, Contain, Protect", the organization's slogan, or for "Special Containment Procedures", or both at once. A wiki was set up to contain all the SCP articles, and then, when problems arose with the wikifarm where it was hosted (Editthis.info), a new wiki was set up at Wikidot, where it still resides—though it's now also accessible through its own domain, scp-wiki.net. There was at one point an effort to put everything at a new domain, scpfoundation.org, but that seems to have been abandoned, or at least put on hold; there's nothing there now except a front page with a number of dead links. In any case, there's a forum thread on the SCP site with more information on its history.

(One more note on SCP-173, I guess, while I'm at it: While it formed the foundation (er... no pun intended) for future SCPs, and while its clinical tone was emulated and even some of the details recurred later—"Site19", where SCP-173 was said to be stored, later became the secure facility housing several other SCPs as well, though it was later generally written with a hyphen, "Site-19"—there is one detail, that, curiously, didn't make its way into the canon. The SCP-173 article mentions an "HMCL supervisor", but such an individual is never mentioned again in any later article on any other SCP, with one solitary (archived) exception. While it was never clarified what "HMCL" stood for, guesses have included "Head Monitor, Containment Laboratory" and "Hazardous Materials Containment Laboratory"—though one person said they tried to look up the acronym and came up with "Human Menstrual Corpus Luteum".)

Naturally, not all the SCPs are equally imaginative or interesting—although, equally naturally, not everyone would agree on which ones are the most imaginative or interesting, and I'll admit that my opinions here seem to go against the mainstream. For example, two of the most popular and most referenced SCPs, SCP-682 the "Hard-To-Destroy Reptile" and SCP-076, "Abel", strike me as dreadfully boring. There are a number of SCPs with widely varying effects that depend unpredictably on some input parameter, such as SCP-294 "The Coffee Machine" and SCP-914 "The Clockworks", which seem to be beloved of the majority of users but which I personally find rather tedious and silly. Similar remarks, to perhaps a slightly lesser degree, apply to the several weird places with apparently extradimensional interiors where seemingly random horrible things happen to exploring teams who enter, such as SCP-455 "Cargo Ship" and SCP-1555 "Facility". But for all these (in my opinion) misfires, there are many wonderfully evocative entries among the catalog of SCPs. I'm not going try to list my favorites here, though, partly because my favorites may not match yours anyway, partly to avoid spoiling the fun of discovering the weirdness for yourself, but mostly, to be honest, because I'm way behind on these World of the Week updates as it is and if I took the time to decide on some particular set of articles I liked best it would take much too much time and set me back even farther. (Besides, I admit I haven't even read all the SCP articles, so it's entirely possible that what would be some of my favorite articles are among those I haven't read yet—there are at the time of this writing more than 1600 SCPs posted (not to mention the "Foundation Tales" and other supplementary material), and, as is partly evidenced by how far behind I am with these World of the Week posts, my time is all too limited.)

(In truth, I've been perhaps a bit hyperbolic of my dislike of the SCPs I mentioned above. They're not really bad... they're just uninteresting compared to some of the others. Actually, since a "Mass Edit" in the early days of the project that saw the deletion of a number of seriously subpar entries that had accumulated, the SCP powers that be have been pretty good about upholding a high level of quality control.)

However, unlike the earlier and thematically similar Holders Series (which also originated on the 4chan imageboards), there's quite a bit more to the SCP Foundation than a bunch of creepy objects. A mantra oft repeated on the SCP forum is that "there is no canon", but that's not really true... and it would be a much less interesting project if it were. While nobody combs every article to make sure no details contradict, and divergent takes on things are especially tolerated in the "Foundation Tales", bits of fiction taking place in the SCP universe, there are nevertheless certain baseline assumptions and established premises that are expected to be followed.

(Actually, after looking into the current incarnation of the Holders Series while writing this post, I think perhaps I'm being a bit unfair to it... the Holders Series does now have some development to its setting, and while it still seems fairly rudimentary, I haven't dug deep enough to see if perhaps there's more there than is immediately obvious—all the extra canon of the SCP setting isn't necessarily immediately apparent on a casual glance either. Hm... if it turns out the world of the Holders has been detailed more than I realized, perhaps it's a candidate for a future World of the Week... But, as usual, I digress...)

The most obvious aspect of canon involves the SCP Foundation itself, regarding which a fair deal of information has been firmed up. Much has been defined about the Foundations's workings, including but not limited to its security clearance levels, the workings of its task forces, and some of the facilities where it operates. And then, of course, there's its protocol regarding the SCP objects. Among other things, each item is assigned an "object class" reflecting how dangerous it is. Objects that can be reliably contained are designated "Safe" (regardless of how damaging their effects may be if they're not contained); more unpredictable objects are designated "Euclid"; and objects especially dangerous and difficult to secure are designated "Keter". This last object class is, of course, where the name Keteria comes from; it comes in turn from a term in Jewish mysticism, referring to the highest of the ten Sephirot of Kabbalah. The SCP Foundation has become well enough known to have inspired a number of (independently developed) video games, probably the best known being SCP - Containment Breach, though I admit I've never played this or any of the other SCP-based games myself (and honestly am not particularly likely to).

(I am putting a lot of parenthetical paragraphs in this post for some reason.)

The world of the SCP Foundation, however, has been developed beyond just the Foundation itself. A few elements began to recur through some of the SCP elements, and gradually a broader world started to materialize. Among the most prominent other elements of this world are what the SCP Foundation calls "Groups of Interest", other organizations that are also interested, for their own reason, in the same kinds of anomalies and phenomena that the SCP Foundation pursues. These organizations are diverse in their goals and methodologies, from the enigmatic alternate-universe Alexylva University, whose mysterious shipments occasionally go astray in Keteria, to the Unusual Incidents Unit, a department of the FBI tasked with investigating paranormal activity. Two of these organizations, the Global Occult Coalition and the Serpent's Hand, now have dedicated wikis of their own; I personally don't find that of the Global Occult Coalition particularly interesting (from what I've seen so far, though I haven't had time to give it much more than a cursory glance), but I think the Wanderers' Library, the wiki associated with the Serpent's Hand, has a lot of potential. (The eponymous Library itself is an aguia which, in the words of the site Q&A, "contains almost every book ever written, and many that never were".

The SCP Foundation wiki is still open to new contributions—as are the GOC and the Wanderers' Library, for that matter. So if you've got an idea for a worthwhile addition to the site(s), go ahead and sign up and try it out. But be warned that even if you do get successfully signed up (and there's a little more to it than you might think—yes, you do have to follow the instructions), be warned that, as mentioned before, there's pretty strict quality control in place, so be prepared for the possibility that your contribution won't survive.