Yahoo! is aiming to deliver a more personalized experience, and to accomplish this task its  decided to remove third-party sign-in from its services. This means users of Yahoo services will have to sign up for a Yahoo ID – if they don’t already have one – as they can no longer use their Facebook, Google or Twitter accounts to access them.

“Yahoo is continually working on improving the user experience, which includes our sign-in process for Yahoo Sports Tourney Pick’Em,” a Yahoo spokesperson stated.

“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 first Yahoo service to implement the change is Yahoo Sports Tourney Pick’Em, a service that centers on the NCAA college basketball tournament which will begin later this month. The change was implemented on Monday and will gradually roll out to other Yahoo services, although no time frame was given as to when this might happen.

The change in the sign-in process aims to deliver a more personalized experience for users, because having a Yahoo ID allows the company to monitor your activities, such as what Yahoo services you are using your ID to sign into.

This is a reverse of the strategy that the company implemented in 2010 and 2011, when then CEO Carol Bartz implemented the use of third-party sign-in for its services. At that time, Yahoo wanted to leverage the popularity of its competitors and their massive user bases, by making it easier for people to access Yahoo services even without a Yahoo ID.

The question now is, will this new strategy by Marissa Mayer work in Yahoo’s favor or will it cost them users? It’s likely that the transition might be unpopular for lots of people, but Yahoo is banking on the quality of its services, and hopes that users won’t mind creating a Yahoo account to continue using them.