According to Microsoft principal researcher Kate Crawford, personal data harvested by marketers is growing so vast and far reaching that it is threatening to unleash a new wave of digital discrimination, one that ordinary people won’t even be able to see happening. Combining the troves of information collected by retailers, mobile carriers, Internet companies and others into massive databases creates so-called big data sets. Computers then troll the data looking for patterns that can be used to make predictions about consumer habits.

Using all of the data that can be amassed about you online, companies can determine your age, race, gender, sexual orientation, etc. without ever meeting you. By tracking seemingly innocuous data, such as the people and brands you “Like” on Facebook, companies could theoretically know enough about you to filter out certain groups they are not interested in hiring without ever conducting a formal background check – which would require applicants’ permission and would leave a paper trail. In fact, employers using this type of data could take measures to ensure that their job listings don’t even show up to be viewed by individuals who are likely of member of a group or class that the employer does not wish to hire.

The amount of data that we are providing to the internet in the form of social media entries, cell phone geo-stamped logins, etc. is simply staggering. Unfortunately, I predict that some employers won’t be able to resist the temptation to use such information in order to discriminate. Watch for this as a developing area over the next few years.

Read more: Big Data Could Create an Era of Big Discrimination