Facebook rolled out new tools for advertisers Wednesday as it prepares to go public later this year in the largest flotation ever by an Internet company on Wall Street. Among the marketing opportunities unveiled at an event held by Facebook at the Museum of Natural History was the possibility for ads on mobile devices -- a so-far untapped revenue source for the California-based social network. Facebook has more than 850 million members and they are increasingly accessing the social networking site on mobile devices. Facebook executives announced three initiatives -- Facebook Pages, Reach Generator and Premium on Facebook -- which they said were \"designed to be used together to drive business results.\" Facebook Pages allow businesses or brands to use the new timeline feature introduced recently to individual users, and overhauls the overall presentation of the page. With Reach Generator, Facebook said businesses and brands will be able to connect with more of their fans. \"Reach Generator guarantees that you reach 75 percent of your fans each month and an estimated 50 percent of fans each week in a simple, always-on way,\" Facebook said. \"Fans will see your message as a sponsored story on the right-hand side of their homepage or in their news feed on desktop or mobile,\" it said. Facebook said Premium lets businesses or brands \"engage and influence people in the most impactful places on Facebook\" -- the right-hand side of the homepage or the news feed on desktops and mobile devices. Facebook said users of the social network who are not fans of a particular business or brand will see an ad on the right-hand side of their homepage. \"For your fans, your story will appear as a sponsored story on the right-hand side and it can also appear in news feed on both desktop and mobile,\" Facebook said. Facebook filed in February for an initial public offering seeking to raise at least $5 billion.