We've talked a lot about privacy on the Internet, so there is probably no need for me to tell you that almost all the websites keep tabs on your online activity and send the data to advertising companies. Most of us are aware (more or less) that we are being tracked; however, what many people don't know is that the data collected isn't always encrypted, so it can easily be intercepted by your ISP (Internet Service Provider) or the government.
Created by Open Effect and Citizen Lab, Tracker SSL is a Chrome extension that lets you know whenever a website uses trackers without bothering to encrypt them first. It doesn't stop the respective site from collecting data about you, but it gives you a heads up so that you can navigate to a different page before feeding any more info. Furthermore, it also gives you the option to tweet a message to the respective website, informing them about this issue. The extension displays a list with all the trackers used by websites, and if they aren't using HTTPS to secure the data, Tracker SSL will display warning messages.
If you are one of those who think that only those who have dark secrets to hide worry about such things, I'll tell you that the collection of such data can be incredibly damaging to everyone's privacy. For example, let's say that the intercepted info comes from content-oriented sites such as forums and newspapers. Based on that information, qualified people are able to create what is called a "pattern of life" (a user profile that contains detailed data about the subject's lifestyle, political views, demographics, etc.)