For most of Silicon Valley's history, the technology industry was generally no farther north than Menlo Park on the Peninsula, and southern Fremont in the east, with the occasional exception (Electronic Arts in San Mateo, Oracle in Redwood Shores). There were the beginnings of a tech presence in SOMA in the dot-com era, but it died when the bubble burst. Tech didn't start to come back to the City until 2006-07 or so.