Based on a diagram @JohnAdams drew on a whiteboard:
FRONT-END /-------------\ /-------------\ - - - -
APPS | HTML Jquery | | iOS/Android | | etc. | COMPETITION
\-------------/ \-------------/ - - - -
/--------------------------------------\
| API - activity |
| - aggregate | COLLABORATION
| - organisation |
\--------------------------------------/
/-----------\ /------\ - - -
DATASTORES | IATI | | OIPA | | etc. | COMPETITION
| Datastore | | | | |
\-----------/ \------/ - - -
/--------------------------------------\
| IATI REGISTRY | IATI MANAGED
\--------------------------------------/
This diagram is similar to that in the slides for his talk at the 2014 TAG: http://discuss.iatistandard.org/uploads/default/40/a386e8913836a7a0.pdf