What do advertising agencies do!?

Chris Rosenkranz: You can try contacting the advertising agencies directly - more likely, if your magazine is local, you can start directly with local companies. The national ad agencies will probably not talk to you until you have a set/attested circulation. Ad rates are set by how many eyeballs you can reach - the more readers, the more you can charge. Since you start at zero readers, until you publish an issue or two, you have no selling leverage.