Using the services of third-party sites puts your account security at risk so we strongly encourage you to avoid visiting them. Additionally, the Zen, items, and in-game currency sold by these sites are often acquired by compromising another player's account and, in many cases, fraudulently using another player's credit card. Purchasing from these sites is not only a major security risk for your account and payment method, but is a violation of our Terms of Service and can result in the permanent closure of your account. If you have witnessed a player buying or selling the above materials, please submit a ticket to Customer Service and we will investigate as soon as possible.
Please refer to the Perfect World Terms of Service Section 15.2, which states:
"You agree to not trade, sell, auction or otherwise transfer any virtual items or goods of any nature outside the game."
and also Section 23.1, which states:
"You do not have ownership of and may not sell, transfer, trade or auction any Accounts, characters, items, coin, Zen or Proprietary Materials, nor may you assist others in doing so, except as expressly authorized by us."
The Terms of Service may be accessed in its entirety here.