Audiences

In marketing, a target audience, or target group is the primary group of people that something, usually an advertising campaign, is aimed at appealing to. A target audience can be people of a certain age group, gender, marital status, etc

This definition is used in media in this case of magazines, becasue each magazine needs a target audience so that it can sell copies.
For instance, the NME magazine is targeted at audiences, like (16-25) as there are articles and infomation that interests them like certain gigs etc.
In many ways magazines like the NME target a few different audiences, as readers of magazines are all different and some people read a certain magazine for a different reason than another person would read the magazine.