Lightbeam is a Firefox add-on that uses interactive visualizations to show you the first and third party sites you interact with on the Web. As you browse, Lightbeam reveals the full depth of the Web today, including parts that are not transparent to the average user.
Not all tracking is bad. Many services rely on user data to provide relevant content and enhance your online experience. But tracking can happen without the user’s knowledge. That’s not okay for some. It should be you who decides when, how and if you want your browsing data to be shared. We recognize the importance of transparency and our mission is all about empowering users — both with tools and information.
Basically when you visit a site that reconnects with a dozen other 3rd party sites Lightbeam shows them all in connected bubbles (and allows you to block them). So take Cracked.com, visiting that webpage also pushes connections to scorecardresearch, sharethrough, doubleclick, cloudflare, dmtracker, nr-data, bluekai, exelator, tru.am, krxd, moatads, newrelic, ricdn, sumome, couple google sites, and then all the social media sites.
MMX boards is almost it's own tiny little bubble, mostly interconnected through image hosts from user images and my google searches.