Here is a link to the website in question.
batmanvssupermanmovie.com. A simple check on
whois.net verifies that the website was created by Warner Bros. in 2002, and was updated on November 8, 2012. And
comicbook.com has pointed out that Goyer mentions this as a possible title for the film during the Superman 75th Anniversary Comic-Con panel.
During the Superman 75th Anniversary panel, Man Of Steel writer David S. Goyer said, “So over in Hall H at the Warner Bros.–I guess most people know now–at the end of the Warner Bros. panel, Zack came out and he brought Henry Lennix, who plays General Swanwick in Man of Steel and we–actually, Henry read a bit from [The Dark Knight Returns] and so the next film we’re making, we’re already in pre-production, comes out in summer of 2015 and it’s–we’re actually not sure whether the title is Superman vs. Batman or Batman vs. Superman but yes, it’s–that rematch, that combination, the two guys onscreen and that’s happening.”
David S. Goyer only gave two examples of what the title could be, so we did a little research, figuring that Warner Bros. would likely have registered the domain name that they would want to use for the title. It turns out that Warner Bros. owns both SupermanVsBatman.com and BatmanVsSuperman.com, which could be used to protect comic book titles as well as movie titles. However, when we added movie to the end, we found out that Warner Bros. had only registered BatmanVsSupermanMovie.com but not SupermanVsBatmanMovie.com.