A pop culture wiki is usually a straightforward thing. If you're creating, say, a Simpsons wiki, you have pages on the show's characters, celebrity guest stars, individual episodes, and a few locations like the Springfield Elementary School, the Springfield Nuclear Power Plant, and Moe's Tavern. Even a typical work of alternate history such as Harry Turtledove's 191 Timeline is much the same: characters, events, locations, and some other pages for, say organizations that don't exist in our timeline. That's because Turtledove's books, like the Simpsons, or Star Trek, are works of fiction, and all wikis based on a work of fiction are going to have certain basic similarities.
On the other hand, even though Robert Sobel's For Want of a Nail is technically a work of fiction, it doesn't present as a work of fiction. It presents as a work of scholarship, with all the attendant apparatus of a scholarly work: footnotes, appendices, a bibliography, and an index. A wiki of FWoaN can't treat it like a simple work of fiction without losing that aspect of the book.
So what I've done in the Sobel Wiki is approach FWoaN as the work of nonfiction it appears to be. By chance, we have this one book describing what we might call the Sobel Timeline, a history that diverged from ours in the fall of 1777. Apart from events that predate that divergence, everything we know about the Sobel Timeline is what we can learn, or infer, from this one book.
The task of describing the Sobel Timeline is complicated by the fact that, as Frank Dana notes in his critique, the author of FWoaN (an alternate version of Sobel) has a set of ideological biases that color his perceptions, and in some intances his descriptions, of events in the book. Thus, it is necessary to distinguish between Sobel recording the historical consensus on some person or event and Sobel expressing his own biases.
So that's what the Sobel Wiki is: a picture of an alternate timeline as seen through the lens of a single, admittedly flawed, product of that timeline.