$5 one day, $10 the next?

I need some help understanding this.

On my Adsense reports - one day I'll have 20 clicks and earn $5; another day I'll have 21 clicks and earn $10. What's up with that? Apparently, not all clicks are the same?

 

Don't worry it's normal. Just means that sometimes low paying ads are being clicked and vice versa.

 

Ok, I can understand that, thanks. Now, this "Page eCPM" number - it seems that when that number is high, my pay per click is also higher - is that right? And what DOES that "Page eCPM" mean, exactly? I read the explanation, but just didn't get it!

 

It's actually an estimation/rate of what you will be earning if you have 1000 visitors.

 

My eCPM has been the same for about 3 months every day. It is so solid that I can't believe it stays exactly at the same dollar value.

I chart CPI (cost per impression) which is basically eCPM / 1000. It gives me good insight into whether or not AdSense is giving my readers advertising of interest on my various sites. My sites with the fewest clicks have the highest CPI. Even factoring those sites in, though, my average eCPM across my entire account is the same month to month to month.

 

i think This happens because of
smart pricing and adwords users changing the
ppc rates.