How do ad networks assist advertisers?

Ad networks play a crucial role in the advertising ecosystem by aggregating diverse inventory sources. This means they collect a variety of ad spaces from different publishers and make them available to advertisers in a consolidated format. This aggregation simplifies the buying process for advertisers, who benefit from a wider selection of inventory without the need to negotiate directly with each individual publisher. By using an ad network, advertisers can access a broader reach and more diverse audience targeting options, which ultimately enhances their campaign effectiveness.

The other options represent functions that ad networks do not primarily focus on. For instance, while high-level analytics can be part of the services offered, it is not the primary way ad networks assist advertisers. Creating video advertisements is typically performed by production companies or creative agencies, rather than ad networks. Lastly, while some ad networks may facilitate relationships or transactions indirectly, their main role is not to connect sellers with buyers directly, as that is typically the function of ad exchanges or direct sales teams.