This is hilarious. Rachel McAdams made a statement that she was not in Spider-Man 4, and the Internet's collective response was akin to "Lalalalala I can't hear you." Then the news sites promptly started cranking out Julia Stiles Spider-Man rumors.
"That's a total rumor, I have to say…I was hanging out in Toronto the other day and someone came up to me and said, ‘I just heard you're doing Spider-Man 4.‘ And I said, ‘Really? No one told me!' It's not true."
And just about every site reporting the denial is insisting that well, McAdams may have had some discussion about Spider-Man 4 at some point in her life so... yeah. But even if we have to give up on McAdams, there's no need to panic in the resulting news vacuum: the web is ablaze with a new rumor, this time Julia Stiles. Turns out UGO has sources that says Julia Stiles contacted a New York casting company about a role in Spider-Man 4.
Now before we get all upset about the prospect of Save The Last Spider-Dance For Me, let's just remember: She contacted a casting company about it. So it's a possibility not the truth. We still have no idea who the Black Cat will be, but there seems to be a consensus that she is in the film.