The savvy Web user knows that the Internet isn't all fun and games. There are plenty of companies out there watching every move a user makes, with an aim to sending their way ads they will click on. But just how many companies are tracking you can be shocking, especially when you don't know what they know about you, and you have never in your life heard of them before. On Wednesday Alexis Madrigal of The Atlantic published a piece he had been working on at least since January, when he first tweeted about Collusion, a plug-in built by a Mozilla engineer that keeps a record of all the sites you have been to in a browsing session and all of their ghostly, behind-the-scenes counterparts: the sites that keep track of what you do on each site. I installed Collusion when I saw his tweet, and I immediately saw that visiting a single site could pick me up more than 20 trackers. But when I read his essay yesterday, the feeling of navel-gazing fascination---Wow! all this time I didn't know that many people were watching me!---morphed into a pretty deep frustration. Here is an account of what Collusion showed me over the course of a day.
10:30 am.
