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Facebook and Google loyalists: Time to dust off your old Yahoo ID.

Yahoo plans to end the ability for users to sign in to the company’s various Web properties using Facebook or Google login credentials.

That means that in the future, in order to access Yahoo-owned and operated sites, you’ll have to do it by signing in via a Yahoo login. The first site to end such support for Facebook and Twitter logins will be one of Yahoo’s fantasy sports properties, Yahoo Sports Tourney Pick’em.

“Yahoo is continually working on improving the user experience, which includes our sign-in process for Yahoo Sports Tourney Pick’Em,” a Yahoo spokesperson told Re/code. “This new process, which now asks users to sign in with a Yahoo username, will allow us to offer the best personalized experience to everyone.”

The move, which was first reported by Reuters’ Alexei Oreskovic, reverses a change made in 2011 under then-CEO Carol Bartz, when the company first began to allow users to sign in to sites like its fantasy sports verticals, as well as photo-sharing site Flickr, using third-party credentials. The idea at the time was to use the massive popularity of Yahoo competitors in order to make it easier for people to sign in to Yahoo sites, thereby hopefully driving more traffic to the ailing company.

This new, Yahoo-only tack, however, is directly in line with a message that Marissa Mayer has delivered since she first stepped into the CEO seat: A more personalized Yahoo will make for a better user experience across all of its various sites.

That is to say, the more Yahoo can understand about you and your activity, the better types of content — and advertising — the company can serve you over time.

That may hurt the company initially. Part of Bartz’s strategy of enabling Facebook and Google logins made for a more porous pathway to Yahoo properties. Not everyone will like the eventual switch, and there will probably be some initial drop-off.

Still, I imagine the grand plan is to make Yahoo “cool enough” that people will actually want to use a Yahoo ID consistently. We’ll see how that one goes.

While Sports Tourney Pick’em was the first site to implement the change this week, there’s no timeline for how long it will be before all other Yahoo properties make the switch.