I have a possible answer to Bob's question of why people get bullied even if they're not 'different'.
Bullying doesn't always happen because you're intrinsically different (sometimes it does, as in racism for e.g.), sometimes it happens because your BEHAVIOR is different.
I'm not an evolutionary biologist, so I don't know for sure, but I suspect from an evolutionary standpoint, different is usually not better. Prehistoric humans, who most likely relied on well-tried hunter-gatherer techniques and extensive teamwork to gather resources, and rigid cultural traditions to distinguish themselves from other groups, probably adhered to very rigid, yet unspoken, rules of behavior. Behaving in a way that was even slightly different from your peers was probably a good way to get brutalized back into line.
This was (again, probably) because nature selects for 'better' and not 'different'. Of course, better means different things depending on your circumstances. In the wild, usually 'better' meant taller, stronger, and better able to work well with others. If you were smaller, weaker, and more awkward, the group didn't want you around. In another age, 'nerds' would probably be kicked out of the group or relegated to servitude.
Then technology got invented, and all of a sudden being tall and strong didn't matter as much anymore. But think about it; who usually achieves the most in modern society? Who gets paid the most, gets respected the most?, gets admired and praised the most?
Top salespeople. Upper management. Entrepreneurs. Senators. Military Generals. These are all people with superior social skills. People who are good at influencing, organizing, and leading others. You almost never hear or see these types of people ever behave awkwardly, or do anything the slightest bit 'weird' unless maybe they're under lots of pressure.
I, personally, have never heard of someone who achieved that level of financial and personal success AND had not mastered social skills.
Bottom line, natural selection for physical strength and overall health may have been short-circuited by technology, but we're still programmed to select for superior social skills and 'social skills' are still defined by a fairly narrow set of behaviors. Deviate, and you're going to get singled out.
Bottom line: Nobody likes people who pick their nose, nobody wants to be the guy with the squeaky, nasal voice who trips over every other word, nobody wants to be the girl who wears frumpy sweatshirts all the time and doesn't use common slang correctly in conversation. These are all behavior things, and they're probably what decides who gets bullied and who doesn't, all other things equal.
The above is why this comic makes sense:
http://imgs.xkcd.com/comics/misusing_slang.png
Think about if you ever heard someone say something like that. Would you briefly entertain the thought of slapping them across their stupid faces? If so, congratulations! You're a closet bully!