I am sure that those of you who are interested have seen this link already Weldonesque comments
So what is canon? Well what Joss says it is. The main question seems to be, what cannon do we except? The comic books and paperback book are not canon, unless Joss says it is....Therefore "Fray", "Tales of the Slayers" and Tales of the Vampires" is, until Joss says othewise, while the Spike and Angel IDW comics are not. Neither is "Pretty Maids all in a Row" etc. So how pure are the fans about canon. Do we stick to it like gospel?
I would say the answer to that is no. Lots of people do not agree that Drusilla sired William, preferring to have Angelus as the sire, for one example. There are many more.
Fanfic doesn't slaveishly follow canon, and would be stunted if it did, it would get in the way of creativity. So why the debate? If Joss says it is canon, it is. We just don't need to follow it in our creative endeavours. Maybe on certain messageboards and communities it is important, but for the fanfic writer and artist, if it gets in the way of a project, then we are AU or AR.
My own concern with a comic being canon is that only a few will follow this story, and know the continuation of canon in this media. So the canon gurus will be a select body who will buy the comic. Others will not. Those who don't buy comics for whatever reason, those who do not last the distance (Of which I might be one), or cannot afford to spend the money and time tracking down perhaps more then 25 issues. That would mean canon will be held by only a few. From what I have read of the comic, I am not impressed. The idea of spending all that time and money on something, even if Joss is involved, doesn't appeal. But I will wait and see what happens before throwing the gauntlet down.
Canon is what Joss says it is, and should lead to some straighforward answers to questions people may ask about what happened to who, when and why. It will not stop people from writing the stories they want, just the learnered (increasingly will be few), who follow canon in all its guises, will have the authority (granted by Joss) to comment and advise others about what really happened when.
Ok my take on it!