"There are millionaires, even billionaires, who sit in their sunrooms watching me work in their gardens and they have no clue what's going on," said Sherri Bohan, a credentialed horticulturist who ran a landscape gardening firm for 30 years and raised two sons as a single mom. Today, retired and disabled, she picks up a free bag of groceries every week at her local food bank. Without the food she says she would go hungry.Silicon Valley's rich do give, and often significantly, but the money mostly leaves the area. Facebook's Zuckerberg gave $100 million to Newark N.J., public schools in 2010; his $500 million gift to the Silicon Valley Community Foundation last year has yet to be designated. The Google Foundation donated about $11 million in 2011, according to its tax forms, largely to global environmental and health projects. "Many people come here to work, but they have no idea what's really going on," said Lisa Sobrato Sonsini, whose Sobrato Family Foundation â¿¿ funded by profits gained as a leading real estate and development firm in the region â¿¿ is the single largest contributor to local charities in the region. "The companies are generous, but they don't see the need directly in front of them, they want to send their money away." Phyllis Kizer, a long time high-tech business analyst, is disturbed by the challenges people in her community face. "Looking at myself, I'm very well paid for what I do, I have no complaints," she said. Once a week, Kizer heads to a low income school where she sits with children, including recent immigrants, helping them learn to read. "I love books, and I love teaching," she said. "I wanted to pass that on. Some of these children, they can really go far, but we need to help."