Besides the fact you can (in theory) spam fake accounts (there is no email check to see if your email is real) and the fact that a good vpn could be used to abuse this site... My feelings are mixed.

A Canadian man was subjected to a Cyberbullying report. The U.S. Congress and FBI in 2012 tried to shut the site down and failed.

Despite the good intentions they only remove a person from their list if proof is provided they're not infected. (Might've read that wrong, but I think that's what it sounds like.)

The dangers of using this site to mess with someone is a real possibility. If someone doesn't like you, and they have decent computer skills, they could serious mess your life up by using this site to slander you. With virtually no way to sue this website in retaliation...

They have good intentions, yet without a way of verifying what's true or not on the site I can't trust it.