Yeah, I know that everything on these applications are technically "traceable".
I have looked into cases in the past involving applications like Facebook, Kik, and Whisper involving these kinds of things and these companies have complied with law enforcement after several years of complains.
However, these new applications like the one I was talking about don't comply with law enforcement. In my conversation with the staff member on this app called NoName he said they don't really have a system for a subpoena because they have never received one for 4 years. I even sent him pictures of the disgusting things I have received and these predator's usernames. However, this staff member said he couldn't do anything. Also, unlike those other apps like Facebook, Kik, and Whisper this app deletes everything off of their server after 7 days making it hard to ever gather enough evidence for a legitimate case. There is also another app called Antichat, which has 1.6 million users. This app has NEVER had a court case against them. They technically have a written out procedure on how to submit a subpoena and submit it to the company but it never has been done. These newer applications like NoName and Antichat make it impossible for law enforcement to pursue anything. The only thing they can do is obtain the app's entire server and then try to recover deleted information. These new apps are enabling bad people more than ever before.

