The mobile advertising company Mojiva announced a new tablet-only ad network today, dubbed Mojiva Tab. While other services have offered ad services that target tablets, this is the first that serves advertising to all tablets regardless of the OS they run.

This doesn’t mean that Mojiva is moving away from advertising on smartphones. CEO of Mojiva David Gwordz says that “Buyers can still purchase smartphone campaigns from Mojiva, but the difference with Mojiva Tab is that there will dedicated resources developing packages, securing new publishers and app content in the tablet space.”

Mojiva’s reasoning is that customers are generally more attentive while using a tablet than a device like a smartphone. If users are paying more attention to what’s on the screen in front of them, they’re more likely to notice ads that interest them.

When Mojiva Tab is launched, it will be deployed in two phases. The first will allow advertisers to buy and display ads using the service. The second phase will allow additional features like device-specific targeting such as certain ads only being shown to users of Nexus 7 devices, for example.

Are you more likely to notice ads on a tablet than you would on your phone?