This Register piece, and there are many other sources, starts with:
Rupert Murdoch is in talks with Microsoft over his plans to delist his newspaper websites from Google.Classic "My enemy's enemy is my Friend" thinking.
It's not really so, they are only a temporary ally at best with a fragile common cause.
The danger lies in your "friend" deciding they don't need you anymore or worse, turning on you once the main enemy is gone or the battle is lost.
I still think Murdoch's strategy is seriously off the mark.