Another map annotation tool and research project:

Stamps

The work is partly done in a context of learning – even computer supported collaborative learning. There is a PC client and client for Symbian – I am not sure if the Symbian client already exist. The features are very similar to ImaNote, but it is not web-based, either FLOSS. I am also not sure if you can use whatever image as the “map” that will be annotatated, or have layers of images in there – like with ImaNote.

The links between the annotations makes the view more like a “discussion map”. Have a look of the ShoutSpace client interface scrteenshot. The link is created when a new annotation is a reply to some earlier one and then draged to some other location.