Forbes reports on the increasingly diverse competition among news organizations in San Diego. The Union Tribune remains the city’s major newspaper, and its Web site generates over a million unique visitors per month. Yet the Voice of San Diego, the nonprofit website devoted to local news, and the 3-month-old start-up, San Diego News Network (SDNN), supplement the newspaper’s reporting in the wake of significant layoffs. The two sites also hope that they will be able to siphon some of the traffic away from the Union Tribune in favor of their innovative ventures.