We want to use an overlay, like a modal dialog, in a landing page to show more information to support conversion without linking to another page or using popups. Anyone have any stats on success or risks? We've considered simple roll-overs to provide some more info, but everyone has raised alarms that we may be introducing a potential technical or usability hurdle for users.

The overlay would display when someone rolled over or clicked a "Learn More" link on the page to provide additional offer reinforcement points to drive the visitors from consideration to conversion. Aside from our own testing, we don't have any sources to cite as to whether this approach can or will impact or aid conversion.

Any insights would be appreciated.