Associated Press: Twitter’s most urgent task is naming a new CEO. But the most formidable one is convincing more people that its service is essential, easy to use and not just meant for celebrities, 16-year-olds and news junkies. To help with the latter, there are big promotions, such as last year’s World Cup push and this year’s expanded content and advertising deal with the NFL to help broaden its audience. There are also smaller tweaks designed to help people find new features or take advantage of tools they might not have been aware of.