On Aug. 27, 1976, a team led by Don Nielson, then assistant director of telecommunications at Menlo Park engineering firm SRI International, drove a specially equipped van 6½ miles south and parked at Zott’s. Forty years later, people read the news on their phones, book beds in strangers’ homes, stalk their friends on Facebook, post videos on YouTube, program their vacuuming robots and fitness-tracking watches, and chase invisible monsters through city streets.