If you have found material on the internet that you believe may be prohibited under the Turkish Law 5651, you can report it either by filling in the form on this web site or by calling 0312 582 82 82 or by email to ihbar@ihbarweb.org.tr.
According to this law access to web sites can be banned in case of including below crimes:

Provocation for committing suicide
Sexual exploitation of children
To ease the usage of drugs
Supplying drugs which are dangerous for health
Obscenity
Prostitution
To provide place and opportunity for online gambling
Crimes mentioned in the Law on Crimes Against Atatürk numbered 5816