We're having significant problems with our Yahoo search campaign. We're getting a lot of visits from junk sites like www.icritias.biz and www.seeq.com (2 sites with a PageRank of 0) and also from www.searchscout.com (looks like it is a spyware program).

I don't exactly how this works because our ads are being handled by an agency, so I was wondering if we could set it up so that only the major sites like Yahoo.com and msn.com are sending us visitors? If so, how?

Thats Content Match (http://searchmarketing.yahoo.com/srch/cm.php). But you might've to shelve out too much of marketing dollars for that!