I don't really know how those applications work. The only problem I have with them is if the person being talked about doesn't have the ability to respond, and for that message to be seen by everyone. If someone wants to say something anonymously, fine - that's their character - but I want to see the character of who they're gossiping about, bullying, to see what the other side of the story is.
One of the most fiendish tactics was to fake a "response" from the attacked individual. An easy way to add even more fuel to the fire, and many/most viewers wouldn't recognize the obvious trick.
Now that would be considered defamation, impersonating a person, etc.. If that can be proven anywhere then that's huge, disturbing, and disgusting. I don't imagine the chances of that coming to light are very high though because people who don't gossip/bully wouldn't be using those apps, so friends of the target wouldn't likely see if there was a response - or if they did I wonder what % of friends would actually ask about the response.
