Online Advertising and Paid Search

Online search remained the major portion of all ad formats.

Basic ads
rectangles and pop-ups
banners and Buttons
Skyscrapers

Other types of ads
Rich media
Video

Basics of Payment :

Traditional model : CPM

Performance model : CPC , CPA or CPL

Who bears the risk :

CPM : Publisher bears no risk as they get paid for every impression.
CPC : Publisher bears risk as it depends on the popularity of the advertiser. The publisher makes money only if the ad is clicked.

remnant inventory :

Low-cost advertising space that is relatively undesirable or otherwise unsold.

Used by “house ads”

Sold via ad exchange or ad network

Ad networks :

Ad networks act as middlemen , brokering inventory on behalf of site publishers

Ad exchanges :

Ad exchanges don’t actually sell any ads. Instead they provide an environment within which advertisers and publishers can buy and sell inventory on a auction basis.