Forum Moderators: open
Both companies have been committed to standard compliance. Both play in their field the role of David vs Goliath, with MS and Google.
I don't think there's much more to it. Definitely no partnership on ownership level or any such thing.
Note that the Opera logo is not on the default start page.
P'raps not but I personally favor more of these types of arrangements from the standpoint of robust compatability. Even a little bit towards a more compliant/cross-browser world is better than what we have now. At least until everyone decides to get on-board with a common set of standards. :)