Hi, this is my first time on the forum and while I tried to do a search of what I was looking for, the problem with such a vast amount of posts is that it becomes harder to search for what you were looking for if it doesn't have specific keywords... So don't think I didn't search out of laziness if these questions have been asked to death, any help would be greatly appreciated. How much on average is the difference between CPM and CPC for a website that pulls in about 100 unique visitors a month? Do CPC Ad's count only once per viewer permanently or per click from the same user? (Ex. if a person looked at your ad, closed the tab, but then went back to click on it again to double check something, does it count as 2 clicks or just 1 since it's from the same IP?) Can you run CPC add's across multiple Sub Domains for different sites? I know CPC ad's are allowed but do CPM advertisers allow their impressions to be run on forums? (Leading to multiple impressions per user.) If so, I don't understand why people would use CPC over CPM if they can drag in a big count of unique users per week.