A lot of these definitions talk about how Palo Alto is rich, and how it's filled with ex-hippies turned Republican, and all that is true. What none of them mention, and what might be the very worst thing about the town, is its banality. Everything - from the style of the buildings, to the cars people drive, to the the clothes they wear, to the food they eat, and even the ideals they hold - is overpriced and bland, more show than substance. There's no art scene, nor even any venues for live music. Both Palo Alto and its sister institution, Stanford, have long made their bread by whoring themselves out to the federal government, doing R&D for defense and intelligence agencies. That's why all the hippies worth their salt left even before they got priced out of the place, and that is what people mean when they say, "Shallow Alto."
At least the CIA turned Ken Kesey onto acid while he was at Stanford, but I don't think Palo Alto can take the credit for that.