For nearly a decade, YouTube has offered a smorgasbord of free music, making just about every song imaginable ? from Top 40 to ukulele covers ? available at a click. But soon the site, whose more than one billion monthly visitors make it the world?s most popular music platform, will start charging for additional perks.

Samsung Electronics Co Ltd aims to restore its crumbling lead in the global smartphone industry in part by ramping up high-end devices with curved screens full of advanced technology that's tough for rivals to replicate.

Investors came to Twitter's firstanalyst day with doubts about the microblogging service's potential. The company left them with a long list of promises about how it will change.