Probably google. If you allow cookies, and sign in to their services, they know who you are. Cookie management should help a lot. Contrary to the above, I wouldn't recommend ghostery. It's proprietary software, made by an ad company. I use ublock(origin) with aggressive lists, SelfDestructingCookies, block third party cookies, and use NoScript. For a little redundancy I have PrivacyBadger, but it doesn't have much to do after using my other stuff. Oh, and I don't use google aside from legacy email(handled with thunderbird).
edit:
It goes without saying, facebook is spyware. They aspire to be as intrusive as google, but aren't quite there yet since their breadth of services isn't as wide as google's.