Copyright infringements and illegal downloads
Copyright infringements via JonDonym-mixes are not efficient and therefore rather unlikely. That is because the user has either to pay for the data traffic (uploads/downloads using premium-mixes) or alternatively the connection is very slow (mixes free of charge). Since, in addition to that, a JonDo-user is not able to act as a server of data, a distribution of copyrighted or illegal material (movies, child pornography et al.) using file sharing services is not possible.
However, for the rare cases in which a copyright infringement could happen, considering the following is important: Due to technical reasons, it is neither possible for the mix operators nor for JonDos to deanonymize past connections.
Web-site-hacking, cheating and spam in forums
Individual users may misuse JonDonym in order to protect themselves against prosecution while hacking web sites, posting insults in forums or cheating in online-games. (Figures in the low two-digit range are reported, yearly, while thousands of users are deploying JonDonym for legitimate purposes daily.) Providers of web sites can send a blacklist containing their DNS-names / IP-addresses / URLs to JonDos, if they do not defend themselves against such attacks otherwise.
In order to pass this blacklist on there has to be a confirmation that a right to represent exists concerning the mentioned addresses. To publicly review the correctness of every particular blocking the whole blacklist is published here. In general, the mix operators will accept the blacklist. But this is not mandatory. Alternatively, you can therefore block the access by yourself using the addresses of the exit mixes which are published here in XML format.