Ask HN: What are the relative values of online marketing metrics?

Dear HN,<p>I've been working on a spreadsheet for the online marketing campaigns of the new company I work at. Currently page impressions, open rates and click-throughs are each valued as equal actions.<p>It seems obvious though that a click-through from a banner or link (whether it be from an email or website) is of more value than a page impression or open rate. Does anyone have any insight into what value we should be applying to each of these metrics (or if there are other metrics that should be considered)?<p>Considering Google ads are done on an auction system I guess they are a good indication of market valuation of each action but I am hoping to hear HN's opinion on this.<p>(Of course please feel free to go off topic.)