Cthulhu Mythos Wiki
The Cthulhu Mythos is such a massive universe of relationships, mythology, and allusions, it requires entire networks of websites, articles, and user-edited opinions to capture it all. Plenty of Cthulhu-based wikis have popped up, user-edited, amateur, and invaluable to fans that want to dig a little deeper than the encyclopedic content found at other sites about Lovecraft and Cthuhlu.
The wikis below reference or support an understanding of the Cthulhu Mythos. Most of them are labors of love created by fans of Lovecraft, of the Cthulhu stories, and of horror and science fiction.
Yog-Sothoth Wiki http://www.yog-sothoth.com/wiki/index.php/Main_Page
It is appropriate that someone would name a Cthulhu Mythos wiki after Yog-Sothoth, one of the two chief gods of the Lovecraft universe. Yog-Sothoth is a god that is everywhere, in all things, at all times, one of the two supreme gods, and it makes a clever name for a massive collection of all things Mythos-related. There are large sections of this wiki devoted to the two most popular Cthulhu RPGs: Call of Cthulhu and Trails of Cthulhu. In fact, it seems like Cthulhu RPG information is the anchor of the site, with supporting details about Lovecraft and the Cthulhu mythos for good measure.
Fully half of this wiki’s categories are dedicated to Cthulhu Mythos RPGs, but the other information is presented well, accurate, and detailed. This wiki’s list of Cthulhu Mythos writers is really handy when I’m looking for a new Mythos book or story to read, and isn’t available at any other wiki or Lovecraft site.
This wiki’s contributor’s page is nearing the 500 mark, and that’s the best thing about fan wikis like this one. You get new perspectives on some issues, information on areas of the Mythos that you’d never studied before but some contributor had, and the built-in network of Cthulhu Mythos and horror fans that already contribute to the wiki.
HP Lovecraft Wiki http://lovecraft.wikia.com/wiki/Main_Page
You can read a lot about the Cthulhu Mythos on this Lovecraft wiki, though the wiki itself is not dedicated exclusively to the Mythos. This wiki appears to be run by writers and horror fiction readers, with most of the sites being bios and references to H.P.Lovecraft, his writer friends, people he collaborated with, other writers in the pastiche style favored by Lovecraft, and descriptions of individual Cthulhu Mythos stories.
Still, this wiki has pages dedicated to the most important characters of the Cthulhu mythos including monsters and human characters. The information here is detailed and regularly edited, based on my most recent visit as of this writing. Judging by the pages that get the most traffic at this wiki, it is most useful as a source of information about the monster menagerie in the Cthulhu Mythos.
Cthulhu Wiki http://cthulhu.wikia.com/wiki/Main_Page
Cthuhu Wiki is a smaller wiki but included as an example of what’s going on in the world of Lovecraft fandom. Sure, this wiki is only made up of 89 articles, but it could be so much more. Read the About:Project page for an example of this fan’s devotion to the spirit of Lovecraft: “Lovecraft himself was unimpressed with the linking of various eldritch entities with the classical elements (Earth, Air, Fire, Water), so preferably this information will not be included, or at best, included as optional information or trivia.” That commitment to Lovecraft’s intentions is the sign of a true Lovecraftian.
Cthulhu Mythos Wikipedia Articles
The Wikipedia pages for Lovecraft, Cthulhu, and the Cthulhu Mythos have lots of good information but they don’t contain lots of supporting material the way the fan-created Wikis above do. In fact, there are only a handful of Wikipedia pages dedicated to the Cthulhu Mythos.
The first is the generic Cthulhu Mythos page http://en.wikipedia.org/wiki/Cthulhu_Mythos.
The best feature of this page is the lengthy section dedicated to source material and references. The page focuses mainly on the concept of Cthulhu Mythos, including a ton of material on Lovecraft and August Derleth, the two biggest names in Cthulhu Mythos history. Most of the page is dedicated to separating the first stage of the Mythos from the second stage, and the names of individuals involved in each stage and a little of their history.
An otherwise useful and well-researched page on Wikipedia about the Cthulhu Mythos in Popular Culture http://en.wikipedia.org/wiki/Cthulhu_Mythos_in_popular_culture starts out with an inaccurate description of what the Cthulhu Mythos is. It is not, as this page suggests, a collection of pop culture references, it is what those pop culture references are point to. The Cthulhu Mythos is the fictional world created by Lovecraft and many writers after him, the god-like creatures and other characters of the stories, and the myths of that universe. But getting back to the page, it is a long list broken up into categories. You can read through Cthulhu Mythos references in music, books, TV, movies, and other categories. This collection can’t be found elsewhere online, so it’s a nice resource for Lovecraft or Cthulhu fans.
As the Cthulhu Mythos expands, so will the need for resources for information on the people and monsters in Lovecraft’s universe, the stories of the Mythos, and the mythology itself. These wikis are just one piece of the Lovecraftian puzzle. The more resources fans of the Cthulhu Mythos have, the better.