I was just over at Hypable reading the reviews of the first of those who have managed to gain entry into Pottermore beta. An example of what they say we will find out is backstory to Professor McGonagall.
That bit is just the beginning of it all. The idea of the amazing batches of information we will receive over the the following years, I expect it will revive fanfiction plots and ideas exponentially.
As I understand it, only information that is contained in the books constitute canon (according to mnff Help section). I know fanfiction writers constantly refer to Rowling's interviews previously for new, fill-in-the-blanks information on new characters. But now that will be mechanical and new information will keep on coming.
My question (more than suggestion, unless it triggers a debate) is whether we still ought to stick to the way canon is currently defined at mnff. Writers here are going to use that information to be inspired anyway, but will it have any effect on warnings placed on the story that utilises information from Pottermore? Not canon or canon?
I understand that this can be wholly sorted when we know the nature of information Pottermore will reveal, but it's starting now and the information will leak already before October, and meanwhile we could give this some thought.