I've been going nuts with pages loading at the speed of molasses in December thanks to all the online trackers my browser informed me I was going through. The more heavily laden a site was with Google Analytics, Facebook, Twitter, you name it, the longer the page took to load, IMO. Something was doing it and those seemed the most likely culprit. Then quite by accident, I found Ghostery
"Ghostery is your window into the invisible web – tags, web bugs, pixels and beacons that are included on web pages in order to get an idea of your online behavior."
Ghostery tracks over 1,000 trackers and gives you a roll-call of the ad networks, behavioral data providers, web publishers, and other companies interested in your activity.
"Ghostery allows zero-tolerance blocking of anything ad related, complete (visible) open communication with ad companies, or countless measures in between - determined by you, the informed web user."
You can choose to block all of these things or some or none. I checked all. They say their very fast scan may slow down pages loading. I've found just the opposite to be true.
Anyway, if you don't like being watched every minute, check out Ghostery