London, San Francisco: Facebook Inc wielded user data like a bargaining chip, providing access when that sharing might encourage people to spend more time on the social network — and imposing strict limits on partners in cases where it saw a potential competitive threat.

A trove of internal correspondence — published online by UK lawmakers — provides a look into the ways Facebook bosses, including CEO Mark Zuckerberg, treated information posted by users like a commodity that could be harnessed in service of business goals. Apps were invited to use Facebook’s network to grow, as long as that increased usage of Facebook.

Certain competitors, in a list reviewed by Zuckerberg himself, were not allowed to use Facebook’s tools and data without his personal sign-off. In early 2013, Twitter Inc launched the Vine video-sharing service, which drew on a Facebook tool that let Vine users connect to their Facebook friends.

Alerted to the possible competitive threat by an engineer who recommended cutting off Vine’s access to Facebook data, Zuckerberg replied succinctly: “Yup, go for it.”

In other cases Zuckerberg eloquently espoused the value of giving software developers more access to user data in hopes that it would result in apps that, in turn, would encourage people to do more on Facebook. “We’re trying to enable people to share everything they want, and to do it on Facebook,” Zuckerberg wrote in a 2012 email. “Sometimes the best way to enable people to share something is to have a developer build a special purpose app or network for that type of content and to make that app social by having Facebook plug into it. However, that may be good for the world but it’s not good for us unless people also share back to Facebook and that content increases the value of our network.”

The emails were released by a committee of UK lawmakers investigating social media’s role in the spread of fake news. They provide more insight into how Facebook achieved its dominance of social media, and how it thought about the value of users’ data, which are provided to the company for free.

Facebook, which runs a network of more than 2 billion people globally, has been interrogated by regulators about the reaches of its power, and the effect of that control on user privacy, the spread of misinformation, and global elections.

Lawmakers obtained the documents after compelling the founder of US company Six4Three to hand them over during a business trip to London, despite the fact that they were under seal in a California court case.

Facebook said Six4Three “cherry-picked these documents from years ago as part of a lawsuit to force Facebook to share information on friends of the app’s users. The set of documents, by design, tells only one side of the story and omits important context.”

In a blog post, Facebook said it will “still stand by the platform changes we made in 2014/2015, which prevented people from sharing their friends’ information with developers,” like those at Six4Three. Facebook said “the facts are clear: we’ve never sold people’s data.”

Damian Collins, head of the committee that released the documents, says the emails show that Facebook shut off access to data required by competing apps and conducted global surveys of the usage of mobile apps by customers possibly without their knowledge.