Ghostery, Disconnect, FlashBlock, AdBlock, and in some browser profile: NoScript & RequestPolicy. I whitelist trusted sites.
The online ad ecosystem is out of control with surveillance: data collection, tracking, device fingerprinting, aggregation, de-anonymization, etc. (and data volumes).
Try this: turn off wi-fi on your computer and try again.
This is why I only use wi-fi when necessary, and also generally keep Location Services turned off on every device I own, unless I specifically need location.
Regardless of where you are, as long as you have wi-fi on and there's a wi-fi router nearby, even in the absence of street view cars or anything like that, all it takes is one person using a GPS-enabled device near you to geo-compromise your router (and in some cases, your wi-fi client devices). Apple, Google, and others use different databases, but if you are on a Mac, then any one person using GPS on iOS near your wi-fi access point has forever pinpointed it in Apple's databases, and when you use Mac OS X Location Services, it draws on Apple's MAC address-to-geolocation database. Similar for Android devices and Google. Or Microsoft devices and Windows.
This one of the reasons I like dynamic IP and change my IP address regularly. So my IP-geolocation location jumps all over my metro area on a regular basis.
Ghostery and Disconnect are essential privacy tools in Firefox, Safari, or Chrome. Also try ShareNot on Firefox, which is experimental, but has somewhat more extensive blocking coverage than Disconnect.
But more fundamental: don't log in unless you have to, log in only in private browsing windows or separate browsers from your other surfing, and also clear your cookies often to keep your not-logged-in browsing cleaner from a privacy perspective.