Everyone knows that Facebook makes its money through targeted ads. By tracking what you look at and click on while using its website, Facebook assembles a detailed profile of you that it uses to figure out what you're interested in, and tailors its advertising to match. But a recent investigation by ProPublica has revealed that the social media company tracks much more than your online activities.

At the heart of the issue is the fact that Facebook buys data from offline sources like retailers, and bundles that data with its own to create more detailed profiles of its users. However, unlike Facebook's native data collection, users cannot see what information these third-party sources have on them. This third-party information can include things like your income level, the stores you shop in, and even the number of credit cards you own.

Unlike Facebook's own data collection, the company provides no way to opt out of this service. According to Facebook, the only way to remove this personal information from their databases is to go through the third-party providers individually, which is a time-consuming and often impossible task. Facebook also regularly changes providers, which means you'll have to repeat process much more than once.

Source: ProPublica

From: Popular Mechanics