Between the NSA, Google, Facebook, and a few hundred advertisers, it's hard to know just who's tracking you, and where. Mozilla, the team behind the Firefox browser, just released a plug-in that lets you visualize the many trackers and cookies that dog your every step online — and it's pretty crazy.
Lightbeam, an extension for Firefox, keeps a record of all the sites that you visit, but also all the sites those sites call out to — from comment systems to video hosting services to dozens of advertisers and analytics services.
It presents all this info visually, with a web of icons representing who's connecting to whom, what sites have overlapping cookies and trackers, and so on.
We all know we're being tracked in some way or another, and expect sites to do it for their own purposes, but seeing it all in one place like this is sobering. Here's what my Lightbeam map looked like after visiting four or five popular sites:

All those triangles are third-party sites to which data is being sent and requested. Just a few minutes into my day, and I'm on the radar of several dozen trackers already!
Of course, some are fairly innocuous things like Google Analytics or , but it's still quite a lot. You can run your cursor over the shapes to identify them, and click on one to reveal its location and who it's trading data with.
However, for the purposes of this article I had deliberately disabled my usual privacy plug-ins, AdBlock and Ghostery. After re-enabling them, I reset my Lightbeam data and visited the same sites again. The result:

Amazing, isn't it? Note that not only are the websites I visited calling out to fewer other sites (and only legitimate ones at that), but there are no connections between the sites I visited — no overarching advertising service can collude with multiple websites and track me all across the web.
Let it build up data from a few days of browsing and you will likely be surprised at the number of connections to and among websites and services you've never heard of. Of course, all this data is confidential, unless you choose to share it with Mozilla — there's a big "contribute data" switch at the top right — although the idea of someone who uses a tool like this then voluntarily sharing that information is a bit absurd.
And, it must be said, this won't detect any deep data-diving being done by the likes of the NSA — that's not something that shows up in the browser.
Lightbeam is free to download, but only works on the desktop version of Firefox right now. Of course, if you want to surf safe, there are measures you can take regardless of platform.
Devin Coldewey is a contributing writer for NBC News Digital. His personal website is coldewey.cc.