A Warez site specialises in the illegal distribution of programs, music, films which have been copied and cracked if necessary. The Warez community is mainly clandestine and uses various tricks to protect its servers from being located. Its many ramifications enable it, for example, to obtain a pirate copy of a film before its official release.
The programs or works may eventually be found on P2P servers, even though the two communities are of totally different origin.
Apart from the illegal aspect, it should be pointed out that programs downloaded from Warez sites (and therefore eventually P2P) may contain spyware, trojan horses or other malware.