So you know what CPM stands for: the cost per thousand ad impressions. But the question is, how is it used? CPM is typically used throughout the advertising industry as a measurement of how much your inventory is worth at a given time. CPMs can fluctuate based on supply & demand, time of year, sales cycles, traffic and other internal & external factors. So, how do you know if your CPM is right? Well, that takes time to determine, and over time you will find the market value of your inventory.
So what's this eCPM (or effective CPM) thing you see when logging in to Adify? eCPM is used to compare ad sellers against eachother. For example:
Your site metrics are 10,000 impressions per month
Ad Rep Firm A: They offer you a CPM of $10 on all the sold impressions per month. They sell 1,000 impressions (10%) during the month and send you a check for $10. Your effective CPM is $1.00 ($10 ÷ (10,000 ÷ 1000))
Ad Rep Firm B: During the course of the month, Firm B sells 70% of the impressions at a $3. At the end of the month, you receive a check for $21.00. Your eCPM is $2.10 ($21.00 ÷ (10,000 ÷ 1,000)).
As you can see, even though Firm B was giving you a much lower CPM, your eCPM was much higher. Ultimately, the goal is to get the number of ads sold per month as high as possible while maximizing the CPM of the ads sold. This will yield the most amount of money for you!
To check your effective CPM, login to Adify and click on Reports. You'll see a table of your most recent statistics. Look for the column called eCPM. You'll see a number for each day and then at the bottom, a Total Effective CPM.