DiiGo annotations on TrailFire annotations are possible:

: http://farm1.static.flickr.com/214/498425196_fd821e1305.jpg

[x][http://flickr.com/photos/fridemar/498425196/ BackLinkToFlickr]

The author experienced this, when he made a DiiGo annotation on a the first TrailMark, starting from its TrailUrl.

You might want to  [http://trailfire.com/Trailfire/trailview/5306 visit this TrailUrl] for experimenting with it. 

-- FridemarPache

* This looks like an interesting technique.  I'll try to apply it after I return from my unexpected travels, the week after next. -- HansWobbe

Hans, thank you for your subtle hint on the Flickr page. Indeed, the flickr community practises consequently back linking. -- fridemar