You likely have noticed that web pages nowadays take longer and longer to load. Even if you have a decent internt connection, there's still a noticeable delay while certain pages load. And it's worse on particular sites.
If you look down to the bottom of the screen when you're waiting for a site to load, you'll often see messages pop up which provide the clue as to why your page is taking so long to load. The server hosting the content you're interested in is working just fine, but the delays are caused because of all the other advertising platform systems that your browser is also being asked to connect to, so your movements can be tracked. This extensive tracking slows down your browsing, increases your internet traffic usage, and decreases your privacy. It means that one advertiser can find out about your browsing habit on another company's web site, if both companies subscribe to the same tracker provider.
Fortunately, there is an EXTREMELY useful and EXCEEDINGLY easy to use browser add-in called Ghostery. Once installed (and it takes just one click to install), you can click the small ghostery icon at the top of your browser window to view details about the trackers that the currently displayed web page is calling on your behalf. In the example below, you can see that the page being viewed was connecting to no fewer that 16 separate tracking networks. By moving the sliders, you can block connections to the trackers, thus speeding up your browsing and preventing companies from finding out about your browsing. And if removing any tracker causes a problem, you just move the slider back. You will be stunned by the amount of "things" that are tracking your every move.
It should be noted that the makers of Ghostery are totally up-front about how they make their money. Anonymous data from their 20 million users of Ghostery is sold to web site operators so that they can find out which trackers are worth using and which are commonly blocked by users.