Basic Definitions Online Marketing

Impression: It is the number of times an Ad is displayed by a search engine or an Ad network or any other source.

Clicks: The number of times an user has clicked on your Ad and went to the website.

CTR: Click through rate (CTR) is the number of times an Ad is clicked (Click) divided by the number of times the Ad is shown (Impression). 
Writing down as a formula, CTR = Clicks/Impressions and CTR% = (Clicks/Impressions)*100
It is considered as one of the important factors which determine the performance of the account in Internet Marketing. Higher the CTR, better the Ad & Keywords are performing.

Conversion: Any advertiser who will do marketing will have some goal to reach. It can be either Brand awareness, Lead generation, Sale of products etc… So when a goal of the advertiser is recorded, it is termed to be as a Conversion.

Types of Bidding:
There are different bidding options present in Internet Marketing let’s see what they are
CPC: Cost per click (CPC) is a form of bidding, in which an advertiser will be charged only when the Ad gets clicked by a user.
CPM: In CPM (Cost per thousand impressions), an advertiser will be charged for 1000 impressions delivered. This form of bidding is generally used in Display Networks.
CPA: CPA means Cost per acquisition and from the name itself, it’s clear that an advertiser will be paying only when a conversion is recorded.

Maximum CPC: It is the maximum amount an advertiser is willing to pay for a click. Most of the times the actual amount charged for a click can be different from Maximum CPC as different Search Engines will have different methodologies to set the CPC.