What is the definition of "Opportunity to view" as it relates to advertising?

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Request for Question Clarification by pinkfreud-ga on 13 Jul 2006 14:46 PDT

Is this what you have in mind?

"Advertising campaigns are monitored by impressions and clickthrus. An
impression (opportunity to view) is the number of times that your
advert is seen by viewers. A clickthru is when your banner is clicked
on through to your website."

http://www.worldcupweb.com/home/advertisers.asp

Depending on the context, the writer may be trying to distinguish
between actual vs. potential ad viewing.  For example, if a commercial
runs during "Grey's Anatomy", the Nielsen television ratings will
estimate how many people watched that program -- and had an
"opportunity to view" the commercial.  But there's always slippage
(people leave the room, read a newspaper, talk to each other), so
everyone with an "opportunity to view" did not actually watch/recall
the ad.  Same principle applies to other media -- radio, newspapers
and magazines, billboards, etc.