Read more at:
https://digiday.com/media/in-first-part-data-play-the-guardian-rolls-out-registration-wall/
In first-party data play, The Guardian rolls out registration wall

To build out its first-party data strategy, The Guardian is asking people to sign in.
In December, The Guardian began testing a registration wall with a select group of its audience, according to a post from chief product officer Caspar Llewellyn Smith. The goal: Improve its products and tailor more relevant ads for readers to ensure the publisher’s financial stability.
“Asking readers to sign in provides us with more information that we can use to personalize our approach in asking for support, to serve advertising (with readers’ consent) and to create a better user experience,” the post said.
Clicking on an article, readers see a message asking them to register for free to keep reading, although registration is not compulsory and readers can click a “Not Now” tab. In April, the publisher started running a similar test, piquing the interest of media onlookers.