Who gets involved in what during the Agile cycle

Well the short answer is that in a highly colaborative environment everyone gets involved where they can add something to the discussion (not just prolong a discussion with anecdotes and trivia though)

Following a conversation I was having with a colleague (a very pragmatic agile manager) the other day I produced the following picture which neatly describes the "layers of the cake" and who gets involved.  Solid lines are primary involvement and dotted lines are more informal, informing or secondary.

I think its pretty self explanatory, cognisant there will always be times when people across the spectrum get involved in odd tasks, I was however very pleased with the form and simplicity of it - so thank you Matt Taylor and I hope you don't mind my choice of colours.