I think the Buffy wiki is, on balance, a pretty useful resource in a lot of ways. But (other than being a Fandom wiki, which is the primary reason I try not to link to it), it has a few annoying quirks which make me wish there was some competitor I could use instead.
Articles are (by default) written from an in-universe perspective and take the post Season 7 Dark Horse comics (and some, but not all, of the tie-novels) as canon. So it can sometimes be a bit unclear whether an article is describing something that was established as fact within the show or something that is comic- or novel-only. (There are also articles on the Boom! era comics, which take place in a completely different continuity again, but those are usually flagged as such.)
The commitment to the in-universe perspective also makes it very hard for the wiki to describe retcons or places where the show's lore appears to contradict itself. (What is the name of Buffy's aunt, for example? And who are the Order of Aurelius?) That's the right perspective in some cases but can be very frustrating if you're trying to answer a question like "when exactly did the writers decide to make [idea] canon?".
Relatedly, the wiki is quite often very bad at properly citing sources: it will reliably give some kind of source, but often on inspection that source doesn't provide any evidence for the assertion it's supposed to be backing up. Just off the top of my head, the wiki cites Welcome to the Hellmouth when describing the Master as the leader of the Order of Aurelius (but the name 'Aurelius' is not spoken once during that episode; I don't think it was until years later that anybody decided this was the name of the collective group of vampires who followed the Master and it's only used as such in flashbacks on Angel) and cites Grave when claiming that Spike had his soul restored by "Lloyd" in Uganda (the episode Grave does not name "Lloyd", crediting him only as "Cave Demon", and does not give a location for where Spike has his soul restored beyond "a cave in Africa").
Reading the linked article, the name "Lloyd" seems to come only from the Season 7 episode Selfless, when D'Hoffryn offhandedly mentions somebody by that name when talking to Willow, and the suggestion that this is the name of the specific individual who restored Spike's soul seems to be pure fanon. (Indeed I've never even seen it suggested outside of the wiki.)
For yet another example of this sort of thing: the article on The Gift claims that this episode was "originally written to serve as the series finale, and several ideas that were used in the real finale were originally written for this episode" and only then cites a single source (Joss Whedon's audio commentary for Chosen). It's not clear at all which of these two quite distinct claims that source is meant to be supporting (in fact I've checked that audio commentary track and I don't think it supports either one). In general the show's discussion of behind the scenes facts or the real world development of the show is noticeably lacking, at least in part because that's not something the wiki contributors seem to care about as much.
As I've complained about before, the wiki is old enough that it's gained some deeply-embedded pedantic conventions that simply don't make sense to outsiders (which is why there is an article called "Jennifer Calendar" despite no character with that name existing on the show: the wiki adopts a convention that favors 'full names' and somebody has unilaterally decided that 'Jenny' must be a nickname, even though nobody uses it that way and it's never hinted as being short for anything until we get a single shot of Ms Calendar's grave).
Sometimes, as you'd expect from a wiki, information provided is just wrong: for example, the wiki claims that Joyce Summers is not mentioned in the Season 5 episode Family but if you go and watch the episode or read a transcript you'll quickly see that's not true (Buffy explains her decision to move out of the dorms by saying that "with Mom not being well, I'm hardly ever here" and later says of her father that "I called him when Mom got sick": these are both very clearly mentions of Joyce Summers even if she isn't explicitly named, and indeed some of the episodes she is listed as being mentioned in don't have her mentioned by name). I think this is also true for some of the show's claims about when particular scenes were added to the opening credits, as these claims offer differ from what I can see on my own DVD copies and from how they were described by people watching the show when it originally aired.
snowghoul
kaledo-art
germansingergirl
