Can someone advise me how I can identify clear abuse of add clicking please? Recently I noted very high click rates that appear to have a definate add word pattern on the adds I'm managing for clients.
Well, "clear abuse" is highly debated on these and other forums.
What do you consider to be tolerable ROI? Express this in terms of unique IPs, cookies, browsers, referring URLs, conversions, money, or whatever you use to track your site's productivity. Anything beyond that might be fraudulent, or it might be nonconverting traffic. But ultimately you have to decide what you will put up with.