Bill Maher's contribution to the It Gets Better Project is really great. It addresses a few things that don't get talked about enough: silent bullying (through being ostracized), and the fact that bullying often has little do do with the person getting bullied.
It also shows that, even though straight folks will never know what it's like to be bullied for being gay, many of us have been bullied for other reasons. However, while the bullying that many straight folks experience is horrible (I know), we can't even imagine what it might be like when exacerbated by religious bigotry, sexual aggression, and familial rejection.
This is where we're failing as parents. We need to encourage our children to not be silent bystanders when bullying occurs. As, Maher mentions, kids do indeed fear that if they get involved the bullying might be turned towards them. But we need to stress to our children that if one kid stands up for a bullied peer, others will almost always join in support.