I followed the open graph object tutorial (https://developers.facebook.com/docs/opengraph/tutorial/) successfully and managed to post an open graph object on my timeline.
I think you forgot to fill Aggregations
on the open graph setting.
It is so simple to set aggregation on open graph setting.
Open Graph activities initially show up only under the Recent Activities section. Once the app has generated considerable traffic, it will start to show up on timelines. The goal for a developer should be to focus on improving the quality of the app, and make it more engaging thereby attracting more users.