A Google Chrome extension has revealed the enormous scale of Facebook’s data collection from its users.  It is reported that the social media giant can track an individual’s activity in order to deliver targeted advertising. This is done by recording as wide an array of information about the user as possible, including their location, page likes, shared articles and even relationship status updates.

The extension was created by ProPublica, a non-profit news company, and reveals information that is already accessible if a Facebook user knows where to find it. Developers admitted that “this is the same information that Facebook itself offers users — buried deep in its site.”

The extension takes the user to the “AdPreferences” page, where the site lists all the categories it uses to decide which ads to deliver to them. The categories are most commonly derived from page likes and which adverts the user has clicked on before. Once on the preferences page, users can choose to remove any of the interests that they don’t think apply to them any longer.

Not all the information Facebook gathers is from site usage, as it can be sourced from other web activity, such as products that the user has looked at on shopping websites earlier in their browsing session appearing next to their Facebook feed.

More troubling is the claim by ProPublica that Facebook “buys data about its users’ mortgages, car ownership and shopping habits from some of the biggest commercial data brokers.” The data gathered can be incredibly specific, with the developers of the extension saying: “we found Facebook offers advertisers more than 1,300 categories for ad targeting.”

With over 1.7 billion users, the value of efficiently using targeted advertising is clearly very high. With such a hugely diverse and global user base,  the ability to send adverts to those most likely to receive them positively is something that advertisers are willing to pay huge amounts of money for.

Facebook’s advertising algorithms are a crucial part of its sustained success. Between April and June this year, the company made £1.5bn, a 186 percent increase on the same period the previous year. Despite the rise of adblockers, with 22 percent of internet users admitting to using one, Facebook saw its revenue from advertising rise by 63 percent in the past year.