Here's how Facebook collects data when you're logged out!

San Francisco: Facebook, on Tuesday, served a clarification on questions how it collects user data when people are not directly using the website or mobile app.

The data collection process directly involves the login to other apps through Facebook. Several websites and apps use FB to make their content and ads more engaging and relevant.

"Apps and websites that use our services, such as the Like button or Facebook Analytics, send us information to make their content and ads better," David Baser, Product Management Director at Facebook, wrote in a blog post.

What Facebook does?

• Facebook helps those websites serve up relevant ads or receive analytics that help them understand how people use their services.
• Soon as you login with a particular website or app, facebook receives information even if you're logged out or don't have a Facebook account.

Facebook, however, said that other companies too get the information of users which provide such services.

"Twitter, Pinterest and LinkedIn all have similar Like and Share buttons to help people share things on their services. Google has a popular analytics service. And Amazon, Google and Twitter all offer login features," Facebook said.

These companies -- and many others -- also offer advertising services.

There are three main ways in which Facebook uses the information it gets from other websites and apps.

"Providing our services to these sites or apps; improving safety and security on Facebook; and enhancing our own products and services," Baser said.

We Don't Sell Data: Facebook

"We don't sell the data. We use the data that people put into the system in order to make them more relevant. I believe people own their content," said Facebook owner Mark Zuckerberg to US Congress.

Facebook is embroiled in a widening scandal that a British data firm called Cambridge Analytica improperly gathered detailed information on its 87 million users.