We've been using Yahoo PPC for quite some time now.
The thing that really bugs me is that we get lots of clicks from sites that are not related to our business and most of those are obviously set up just to earn money from PPC. Visitors to our site from these PPC sites rarely go any further than the page they landed on.
I'm not sure if it's fraud or not but it's costing us money.
Is there a way to set up our Yahoo PPC campaigns to just get hits from the Yahoo site itself?
Unfortunately there is no way to get Yahoo! only traffic. I know it's a feature that a lot of advertisers want but seems to be ignored. You can try using the blocked domain feature, but it can be time consuming and there is a limit of 250.