I think it's this statement that people are more quoting than anything else:http://www.wired.co.uk/news/archive/2013-05/22/xbox-one-faq
Will Xbox One use dedicated servers for multiplayer games?
Yes. Microsoft has 300,000 servers in place for the Xbox One's launch and games are no longer hosted on a player's own Xbox console. If you've ever felt the frustration of a multiplayer match ending because the host switched their console off, prepare to be thankful it'll not happen anymore.
and other sites have said it (though none have sourced it). we'd have to go back and dig through the articles again as they've been buried by the "there are no games!" articles that exploded during the reveal.
like this one:http://www.idigitaltimes.com/articles/17712/20130521/call-duty-ghosts-xbox-one-ps4-release.htm
The strength of Xbox LIVE (along with the strength of Microsoft's checkbook, no doubt) was the reason the exclusivity relationship started in the first place. And, since it was announced today that Xbox LIVE will feature some 300k dedicated servers for the next generation of online play, it really should come as no surprise to Sony fans and future PS4 owners that the Call of Duty: Ghosts Xbox One release date could feature some exclusive content that will not be a part of the Call of Duty: Ghosts PS4 release date.
basically, no articles out there definitively say one way or the other way for COD: Ghosts.