In this photo taken Thursday, May 3, 2012, men stand near an entrance to the main public library near Twitter's new headquarters in San Francisco. With Twitter?s new headquarters set to open there soon, residents of a San Francisco neighborhood notorious for crime, drugs and homelessness remain among the least likely to have any way to send a tweet, much less access to basic goods and services. At a recent weekend ?hackathon,? engineers and entrepreneurs sought ways to use tech to help people in the Tenderloin and Mid-Market Street area find food, housing, healthcare and jobs. In the process, city leaders hope to ease tensions between needy locals and newly arriving startups flush with cash. (AP Photo/Eric Risberg)