I do not believe that social media is at fault for these incidents, Josh was a fake profile misusing the website and what it was originally published for. Social Media should seek ways to prevent fake profiles from being made in order to prevent this incidents. Although it can be argued fake accounts are used for amusement purposes in the vast majority of scenarios they are abused and look to cause a reaction from others viewing the account.
I think the parents of the victim should have monitored their daughters use of the Internet more effectively but teenagers are very good at sneaking around and will use social media regardless of their parents opinion. On the other hand the parents of the perpetrator in this scenario are extremely liable for the cruel things said over this account. To begin with they should have taught their daughter how to handle a dispute with her old friend in a better manner, but more importantly the mother was aware of this account and as a direct result of this mockery, another girl her age committed suicide. The mother could have prevented this situation immediately after she became aware of it, rather than encourage and be present while her daughter was hurting the feelings of Megan.
Social media is not criminally libel for this abuse because they created the website for completely different purposes. It was the users abuse who caused the child's death. Shooting someone with a gun is not the inventor of a guns fault, is it? Social media should require verification of identity so that users cannot make these fake accounts. They could also monitor the use of social media for children under a certain age because we aren't going to stop them from creating an account to be 'cool'.
I think that Megan's neighbor should be prosecuted for her actions, although Megan was mentally unstable in one way or another, no child should be made so miserable she feels the need to end her life. This was abuse of her freedom of speech and criminal charges should be along the lines of involuntary manslaughter. This tragedy will haunt the victims family forever and repercussions should be taken against the perpetrator and her family.