No free service is genuinely free. If the service doesn’t charge you for access, then it’s selling your data to recoup the cost of servers, employees, and hopefully net a profit. With that in mind, Twitter is alerting users it will start sharing more data about your ad-viewing habits to its advertisers.

Online advertising is always a tricky business. You only want to keep paying for ads if you know they’re effective. How you measure that varies, but it can be views, clicks, or even an uptick in sales. Twitter needs to sell ads to survive, and part of that process means showing whether or not people interacted with ads.

Until recently, you could opt-out of that data sharing practice on mobile. By opting out, Twitter couldn’t use your data to prove people interacted with ads you’ve seen or clicked on. Now, Twitter has tweaked the setting that controlled that behavior.

If you’re in the U.S., you can no longer opt-out of “mobile app advertising measurements.” Instead, the setting will continue to let you opt-out of other data sharing options, like your interests and web tracking. Twitter doesn’t share your name, email address, or phone number, regardless of your settings.

European users won’t see a change, however. Thanks to GDPR, they have to opt-in to share data (as opposed to opt-out in the U.S.), and that continues to be the case.

Still, the data Twitter will share is relatively limited. It centers on how you interacted with an ad, if at all. That data may help the service charge more to display ads, which will keep the company going (and maybe even let it reach profitability). It’s mostly a small price to pay to keep Twitter alive. After all, the only thing worse than Twitter is broke Twitter.