Unique Visitors
These are users and visitors who are counted by using visitor ID, domain
name, and/or a cookie. Unique visitors do not include repeat users during
a specified session.
Page Views
The number of times a visitor requests a page which can contain a specific
ad.
CPM
Cost Per Thousand (Roman Numeral) impressions. The price paid by an
advertiser for a web site displaying their banner ad a thousand times.
Clickthrough
The act of clicking a banner, or other ad, which links the user
(typically) to the advertiser's Web site.
Impressions
An impression is the industry term for delivering an ad via
a Web page. Technically, an impression is a call from the ad engine to the
ad server to return a banner graphic or advertisement.