Ghosts are something I think about a lot. Especially when I travel to San Francisco -- a place where I lived and worked for about 11 years, starting in 1993. I have been here all week, working, visiting friends, sharing meals, sashaying through old haunts. All of this is done, as you may imagine with the ghost reference, with intensely mixed feelings. For after all, this is the Bay Area, the Peninsula, Silicon Valley -- and I was here during very formative, dramatic years personally and professionally.