Reach
The numbers of different target audiences who see an ad or message.
In effect, it is a measure of popularity.
Examples: Local news has a smaller reach than national news; a message aimed at all sports fans has a bigger reach than one aimed just at hockey fans.
In measuring Web site traffic, reach is the percentage of all Internet users who visit a given site. For example, if a site like yahoo.com has a reach of 28%, this means that out of a random sample of one million Internet users, you find that 280,000 of them visit yahoo.com during a given period of time.