Since I was a kid in this industry, the standard terminology has been to “buy media” meaning stick an ad somewhere, and hope somebody you want to reach sees it, and takes action as a result. However, the reality is that we have just rented an audience from a newspaper, TV or radio station, not bought them.
The net has changed this, as with almost everything else. Now we can buy an audience, over time by developing content that engages and draws people back again and again, encourages sharing of and comment on the comment, effectively building digital “stock in trade” that is stored for access when appropriate.
In other words, at last, we are able to create stock that we can use in the selling process, or in the case of on line retailing, a sale results directly from the stock on the net.