Twitter on Thursday started to roll out a major redesign of its interface in hopes of simplifying users\' experience, as well as new brand pages to strengthen its relationship with advertisers. During a press conference at its new headquarters in San Francisco, Twitter Chief Executive Officer Dick Costolo and co- founder Jack Dorsey unveiled a whole new look of the social networking and microblogging service. According to an introduction video, the new homepage features profile on the left and the timeline on the right, which are flipped from the current positions and take less space than they used to. Three new buttons were also introduced as \"Home,\" \"Connect\" and \"Discover.\" \"Connect\" shows users who has mentioned them and suggests some accounts they might want to follow. \"When you use Discover, you\'ll see results reflecting your interests -- based on your current location, what you follow and what\'s happening in the world,\" said Twitter. The overhauled interface is only available to a small group of users at first and will be rolled out to all users over the coming months. It will also remain consistent across Twitter\'s official mobile apps. Twitter has launched a page fly.twitter.com to explain all the changes. Along with the introduction of the redesign, Twitter also announced new brand pages on its platform. A total of 21 brand partners will be included in the initial launch, such as American Express, Best Buy, Bing, Coca-Cola, HP, Disney and Nike. Analysts said Twitter has ambitions to compete with similar brand pages from Facebook and Google+. According to eMarketer, Twitter\'s global advertising revenue is expected to reach 139.5 million U.S. dollars this year and approach 400 million dollars in 2013.