Generally the producers of the site moderate the behavior, and with most every website there is a way to report someone who has harassed you online
On facebook, with any comment or post, there is a "flag" button next to or under it. When you press it, it gets someone reported to the authorities.
Netiquette
Local Cyber police is moderating Online content all the time. As you can with the recent National Security Agency leak they do moderate a lot of stuff online and know when you are breaking the law online.
You can buy parental contol software, or for a large (5+) network of computers you can set up a proxy.
netiquette
Usually the e-mail server helps monitor what is going on. Also users when they report spam and other issues it helps the servers fix the issues and get rid of those misusing their service.
helps moderate heart rate
Passive
Passive
Passive
Passive
Passive
A moderate fever helps many of the bodies defense systems work better and slows down the growth of many pathogens