Julian Sanchez explains how online harassment can add up:
One reason "cyberbullying” may present special problems is that the Internet and social networks dramatically increase the realistic number of people who can pile on a single victim in a short period of time. Each aggressor might rationalize their own part in the distributed bullying as just one or two comments, though the victim perceives an overwhelming assault when these are all combined.
For an analogy in the physical world, we can look to street harassment, which is enabled by the high volume of anonymous, brief public interactions characteristic of urban environments. Some men, of course, engage in vulgar and intimidating speech that anyone would consider harassing in itself. But often, the harassment is a distributed phenomenon. Many of us would not particularly mind a single stranger yelling out "Hi, gorgeous" or "You look good today!" once every other month—and I’ve seen men (inexcusably obtuse, to be sure, but not obviously malicious) react with genuine surprise when such remarks are not welcomed as compliments, not realizing they’re the tenth person in as many blocks to volunteer a similar comment to the same woman.
The Dish 