Advertisers: Advertisers are those companies looking to acquire leads, prospects or customers and have a budget to do so. The ways in which you can buy online Traffic are CPM, CPC, CPA or CPX models. See individual terms for explanations.
Advertising Network: This is a company or companies that own (or use a tracking platform) to distribute advertising across multiple sites. The Network can carry a huge range of advertisements and run across multiple Publishers or Affiliates target certain  
Affiliates: Affiliates can also been known as Publishers, traffic sources or Partners are websites or media owners that distribute advertising for Advertisers. This can be across all forms of Traffic (see main section for more details on Traffic types).

Affiliate Networks: These are a collection of many Affiliates (sometimes thousands) arranged on an online platform or site to enable Advertisers to reach many consumers without having to make agreements with hundreds of Affiliates.

Banners

Behavioural Targeting: The anonymous targeting of a user (or IP address’ behaviour) with regards to actions performed on the internet. This can include but is not limited to: inputted search terms, browser history, clicks on adverts and so on.
Caps: Caps are used to limit the frequency of usage. This can be the frequency of the number of times a banner is shown, email sent or other level of engagement. Caps are most often used in Display advertising where an Advertiser caps the number of impressions his /her campaign runs or the frequency of which it is shown to the same user.
CPA: Cost per Action or Cost per Acquisition. This is the ideal measure for Advertisers to buy traffic as each Action should have a monetary value that can be measured against the associated Traffic costs.
CPC: Cost per Click. This metric is used to determine the cost of each click to your website / Email campaign / Application / Download etc.
CPM: Cost per Thousand. This metric is widely used in Online Marketing and is a
Direct Response
Display Advertising
eCPM (Effective or Equivalent Cost Per Thousand)
Frequency Cap
G
Harvesting
Interstitial
J
Keywords
Leaderboard
Lead Generation
The process used to acquire prospective customers
Monetise
N
Optimisation
Organic Search
Pop Up
Pop Under
Publishers
Paid for Listings
PPC
Pixel
Performance Marketing
Retarget
Search
Spam

Skyscrapers: Banners that are 120 x 600 pixels in dimension.

Traffic