400M*.01 would actually be $4M But basically CPM means cost per mille (thousand). I believe 1 cent per pageview is absurdly high for most CPM banner ads, with

400M*.01 would actually be $4M But basically CPM means cost per mille (thousand). I believe 1 cent per pageview is absurdly high for most CPM banner ads, with the real amount being closer to $.003. It all depends on how valuable a demographic you have (or mix of demographics) in the eyes of the advertiser, though.