Right, I calculated just for one user. However, if you have 200000 unique visitors, without any auto refresh, you will get millions of impressions for sure
The math is correct, perhaps I need to make this more clear. I only need one ad unit on the header and publicity is rotated automatically using Ajax. See grooveshark.com as an example of this approach. If instead of an ad unit I would add the code for the page view tracker, then it would silently increase the stats to huge numbers. This would skew the statistics and give the impression that I'd maintain a site with millions of page views. --------- Just for the record, I don't rotate automatically publicity nor tamper with stats.