I an slightly puzzled by something and perhaps someone could shed some light on it. The number of impressions for individual ads seems to vary enormously, with peaks and falls which do not follow any particluar pattern. It isn't an overall drop in all ads, but periodic variations in individual ads. I would have thought that if someone has, for example, three ads, with equal share of the overall weight, then the number of impressions for each will be roughly the same over time, with each getting approximately one third of the available weight. Obviously there will be certain times when all impressions are down, for example the 4th July holiday weekend in the U.S. However, this variation doesn't follow any such pattern. Some might say this query belongs in the weight category, but it isn't a question about weight, it's about impressions. Any explanations?
Probably has more to do with the caching system than anything... like once you are in a site's cahce, your ad is going to get equal number of impressions as the other 399 ads in their cache for roughly 4 days, so...
...one day your ad might show on a high volume traffic page, a popular portal's homepage perhaps whilst a few days later you're on an obscure, tucked-away 7 tiers deep page no one ever sees.
I'm glad you asked this question Hair, I've been wondering the same thing. So, Shawn, would a stat that tells us the number of pages our ad appears on be a more even stat...... ie, several ads of equal weight would appear on an even (though not exact, of course) number of sites? It gets confusing when you add weight, expect a rise an impressions because of it, but then stats are irratic so it's hard to tell if there has been a proportional increase. As always Shawn, thank you very much for such an outstanding, beneficial, set of tools, Chris