This is an interesting idea - especially the API aspect of it. Have you considered partnering with some well known players to help launch the service?

Especially given the negative experiences people have with Groupon I think some social proof to show people the positive experience would be useful.

I'm not sold on the name either - 72hdeals? Are all deals 72hours long? I'm not sure I get it.

Good design.

Overall I think this could be a very exciting idea and potentially disruptive!