I don't know who is more evil, Google or Facebook, but I'm leading towards Google being more evil and Facebook being just as greedy, but has a history of being less responsible. So, choosing the greater evil is simply a matter of opinion, at that point.
We know that Google is in the business of monetizing what they know about you. Facebook does the same, but they're not on the same scale. Google is much larger and farther reaching. I'm sure there are others who will argue this last point, but that's another debate, altogether.
Google is greedy, because they truly want to rule the entire online world and monetize all of it; and while Facebook does try to improve security features and have made significant progress when you consider where they started, they also want to monetize everything they know about you. Their service is more personalized than the overall Google experience, which means they have a greater responsibility to anonymize and protect your data. Unfortunately, their failings in this regard have been all to frequent and public.
Google would like for your experience to be more personalized, just as it is with Facebook, which is why they created services like GMail and G+. Their purpose in doing so is to create a service that ensures you are always logged in; that makes it easier for them to tie all of your activity together, increasing the value of the data they collect for their advertising engine. Once you log into either of their social products, your Google searches will also be enumerated in relation to your profile. They originally tried to encourage this with their iGoogle product, but it was not as successful as they would have liked and is soon headed for the chopping block.
The two companies therefore, have very different approaches to the same objective. However, if you have any Facebook or Google service, virtually every online activity you make is being tracked and enumerated. No matter how much you think you are being safe and protecting your online identity, your life is an open book to them and isn't likely going to change very much in the near future.
What can you do about it? Well, I know a few people who refuse to use Google or any of their products; but frankly that makes it very hard to function online. I know more people who have no Facebook account or have recently abandoned it. Yes, they may use several online services, but not the big two and in doing so, they have managed to spread their activity out, so that it has become less connected and therefore, less marketable. Make no mistake though, they are still being enumerated. Everything online is. Theirs just doesn't correlate as well with one particular profile or demographic.
I'm obviously not one of those people. I don't mind that my activity is being monetized, but I limit what I share, in order to protect myself and my family from the criminal elements in society. I'm not quite as concerned about the companies, themselves; although, I'm not naive or completely free with my information, either. I only fill out the minimum amount of profile information on each service. I don't sign up for an account with every service I use either, unless it provides me with some personal benefit, such as better features. I don't use my real name, as those of you who know my online identity are already aware. I also minimize advertising. I opt out of every ad service I can, block others with host files, firewalls and similar services and turn on every security feature I can.
Another thing that I could do, is log out of each service whenever I navigate away from the page, but that would be extremely inconvenient. I could also use multiple browsers; one for Facebook exclusively, another for Google exclusively, and a third for everything else. That would also be less convenient, but severely hamper the ability to track my activity and tie it back to my profiles.
So, there are plenty of strategies one could employ, in this regard. The question you have to ask yourself is how much effort you want to put forth and how concerned are you about being tracked. In the end, virtually everything is being tracked and monetized, so educate yourself, be smart and safe. You can't stop the vast majority of your activity from being monetized, but you can anonymize it, minimize it and take advantage of all the security features offered to you with each service.
The thing that people seem to overlook is that all online companies have a legal and moral obligation to protect your information, online. Why? Why is there a need for security features and privacy protection, in the first place? In the end, it's not the companies you have to worry about. The greatest threat to your personal safety comes from hackers, stalkers and other undesirables, in the general populace, who are attempting to steal your information or otherwise use it to directly do you harm. So, to answer the question I originally posed about who is more evil, Google or Facebook, I answer "neither". Both are inherently amoral. The general public however, has many elements who actively wish you harm. They want to steal your money, steal your online accounts, steal your identity, ruin your reputation and in the most extreme cases, do you or your family, direct physical harm. So, be smart and keep those people foremost in mind whenever you share information online.