The victim is hurt in ways similar to physical bullying and more. Their emotions are shattered, they may view themselves as inferior or weakened compared to before, and many enter a deep stage of depression.
The bully is harder to punish, which only encourages them to continue on their path of being a nuisance. However, many bullies are also unable to see the effect of their attacks, which may remove the joy they once received from doing so. They also may come under attack from "social vigilantes" who may gain knowledge or threaten the bully using cyber attacks. An example is the famous group Anonymous.
The bystander can see several shifts in behavior, such as a decrease in the use of social media or a reduction in their self-worth. Those unwilling or unable to stop online bullying typically blame themselves for being weak and incapable of doing anything. However, there are many steps they can take to stop internet bullying; it just takes some time and understanding to do so.
I hope this helps! :)