Watch out before you accept those new terms and conditions from Twitter: that new legal stuff says they can now spy on the other apps you install on your Android or iOS device and report back to the company.

Twitter launched a support page to tell consumers what the new terms and conditions are about, claiming the changes will actually be a benefit to its users — however, it means that Twitter will be able to advertise services and apps to you based on what you’re downloading, according to Forbes.

With this change, Twitter will know what certain people in certain demographics are downloading, allowing for more targeted and profitable advertising. For example, if Twitter knows that you use Uber, it can sell advertising to Lyft in an attempt to get you to switch.

Twitter said in its support page that it would only collect a list of applications installed, and not any of the data within those applications. Most probably won’t be bothered by the change, but for those who consider it an invasion of privacy, there is a way to opt out.

Twitter’s data gathering will mean changes beyond more targeted advertising. It will also affect what Twitter users you’ll be recommended to follow based on your interests, as well push relevant tweets into your timeline.

Android users who want to opt out of this feature need to go into their settings and deselect “Tailor Twitter based on my apps.” For Apple devices, you need to go to settings, and then Twitter, and then privacy and remove “Tailor Twitter based on my apps.”