Can anyone help me to understand? When I log into my account on adsense At the top of the page is some headings. I understand what the click and of course the earnings means but what does the rest mean:

• page impression
• page CTR
• Page eCPM

I am aloso wondering why one day I earn nothing and other days I earn a couple of dollars? How do you earn consistently? Can anyone explain all this to me?

Page impressions - number of times the Ad is shown

CTR - click through rate - % of time shown ad is clicked

cpm - Cost per 1000 impressions. From a publisher's perspective, CPM is a useful way to compare revenue across different channels and advertising programmes. It is calculated by dividing total earnings by the number of impressions in thousands. For example, if a publisher earned $180 from 45,000 impressions, the CPM would equal $180/45, or $4.00.

If you want consistsnt income, have a high traffic
With few humdred pageviews per day, there is going to be a lot of variation. It will even out if you have a few thousand page views per day, atleast.

To add to the other answers:

Page impressions = number of times a PAGE is shown that contains ads. You could have three ad units, each showing 5 ads, but this is counted as only one page impression.

CTR = number of clicks / number of PAGE impressions

eCPM is not very useful. It tells you how much you would make if you were being paid per 1000 impressions. But you're not being paid that way, so it doesn mean much.