What is Yahoo! intention by denying access via Google and Facebook?

Yahoo! users are being asked to login using only a Yahoo account. Logging in with via Google or Facebook will eventually be removed according to Yahoo!

Currently logging into Yahoo! services via Google and Facebook are allowed and provides Yahoo! access to the billions of users available through Google and Facebook.  Yahoo! cites that the changes to limit Google and Facebook in March are being implemented to improve the "streamlined sign-in experience" and to to consolidate to "single account and password for all Yahoo products, across devices"

Although the changes to logging in only affect the Tourney Pick'em at the moment, eventually all fantasy sports played through Yahoo! must use a Yahoo! account.  Yahoo! is currently the leader in fantasy sports and is ahead of ESPN and CBS Sports. Facebook and Google do not have any meaningful forays into the fantasy sports market.

FtSb Says: Sign in goes beyond fantasy sports. Yahoo!, Google and Facebook are in a death match to win the dollars attributed to advertisement with their platform of services. Fantasy sports is important to Yahoo! as the traffic and usage it generates profit for its display advertisements.  Yahoo! could be using its market leader position in fantasy sports to drive users to its other services and content in an effort to best Facebook and Google. Yahoo! would also be moving Flickr and its other services away from Google and Facebook login. We've said that the goals of game providers such as Yahoo! are different than the game providers such as the NFL. Thus the actions of Yahoo! in this case, would be to the benefit of Yahoo!. The NFL would benefit by having all users of Yahoo!, Google or Facebook be able to access fantasy sports. It makes sense that the NFL has separated its dependence of Yahoo! and started its own game provider platform on NFL.com. The NBA and MLB should follow suit.