YPN has banned sites that receive a high percentage of international traffic too.
Yahoo Publisher Network responds to the complaints on its blog saying the accounts were closed due to "traffic quality issues":
Quote:As noted on certain message boards, some publisher accounts have been recently closed. These account closures were based solely on traffic quality issues
Yahoo! Publisher Network is still an invite-only beta program. As such, were constantly refining the procedures and policies that will help maintain a quality network for our publishers and advertisers. And we wont release the product to the general publishing community until we are able to serve our constituents needs well.
This is a learning experience for everyone, one of the main concerns for our 100,000-plus advertisers who participate is the quality of traffic they receive. For advertisers, we need to consider the source of traffic, the site content, click activity, and the overall quality of leads generated for our advertisers.
As publishers you are also concerned with quality the quality and relevance of the ads you receive and how well they monetize on your sites...
full article:
http://ypnblog.com/blog/2006/05/04/maint...y-network/
YPN goes on to stress the importance of following the TOS (
https://publisher.yahoo.com/legal/tnc.php)