Ecosystem updates

I have started adding material to the DD Ecosystem wiki pages. Where
there is new material, I have added a yellow star. A white star
indicates where further new material will go, and suggests what it
should cover. (Latest additions are in the Trust section.)

I hope this approach will help people see easily how the document is
evolving (although for a detailed view you can use the wiki diff
system).

Suggestions regarding the wiki versions of the group documents should
generally be accompanied by new/alternative text. There's no point in
saying "I don't like paragraph 3", for example, without also providing
some alternative text that you _do_ like.

---Rotan.