As you travel the Web, ad trackers, beacons, and similar technologies track where you go and what you do --- but there's something you can do about it. I've got simple solutions that lets you kill them all, or only those you think are doing you wrong.
First, an explanation of the problem. These trackers, beacons and other technologies are a marketer's dream because they send them information about your surfing habits. Profiles can be created about you --- and they can be combined with offline information about you as well.
They're everywhere, even in the places you'd least expect them. For example, the Web site of New York's Metropolitan Museum of Art has a whopping 28 of them -- and you wouldn't expect a museum to track you this way. If they're on that Web site, you can imagine how ubiquitous they are everywhere else.
They're more problematic than just invading your privacy. They can also cause Web pages to load more slowly, or even stop them from loading altogether.
The simplest and best solution I've found to the problem is the free Ghostery. It's a browser add-in that runs on Chrome, Safari, Firefox, Opera, and Internet Explorer. (No version yet for the Windows 10 browser Edge.) The mobile version runs on iOS, Android, and Firefox for Android.
When you visit a Web site, click the Ghostery icon and you'll see all of the trackers on the page. You can then turn any off. When you turn one off for that page, you turn it off for all other pages as well. At any point, if turning off causes a problem, you can turn it on again.
There are plenty of other features. When you go into options, you can with turn off all ad trackers or beacons with one click on every site you visit, for example. You can also whitelist sites and pause your blocking.
Note that Ghostery doesn't block ads -- it's not an ad blocker. You'll still be delivered ads, although they might not be targeted directly at you if you turn off various trackers.
If you're looking for another solid free program that stops trackers and beacons, try out Privacy Badger from the Electronic Frontier Foundation. It works as an add-in for Chrome and Firefox. It doesn't let you turn off individual trackers like Ghostery, but it's still a great solution.