Cost Per Click is the revenue you earn each time a visitor clicks on your ad.
To make $100 everyday you need 40,000 Page Views/day Or, 400 Clicks a day @ 1% CTR and $0.25 CPC.
With my keywords you need 1000 times less traffic to earn good money.
Only Long Tail keywords - from 4 words in sentence!
With CPC, Volume, Difficulty.