From the prime mover at the Vivaldi team:
My friends at Google: it is time to return to not being evil
Basically, Google shuts off income streams of affiliates who stray from the party line: how that affected Opera before it went to the dark side and how it affected Vivaldi until recently. Jon von Tetzchner was the man responsible for Opera until it went south and now spearheads Vivaldi. This is a very interesting article on the direction of Vivaldi and why it deserves your support.