Reflecting on this years theme, where is the intersection (if any) between 'traditional' improvisation and 'contemporary' improvisation? In what ways are contemporary improvisational practices an extension of traditional practices and in what ways are they a brand new activity?  

contemporary improvisation can manipulate 'unimprovised' objects to improvise a new song  

For me the use of computer programs was the initiation of the transcendation of "traditional" improvisation. The traditional improvisation was imrovising with a set of rules, like in jazz you needed to learn modes and ways to move through modes to be a good improvisor. Free Jazz was an attempt to liberate the musician of these rules, but in practice it didn't really work, the musicians would still follow rules, though at least unconscious and not so well known rules... With algorithmic composition one could finally combine the advantages of improvisation and composition. The computer would care about the rules, defined in advance in a compositional process, and then the performer would just improvise with these newly created tool. Finally the intimate world of here and now of the improvisation and the profound depth and interconnections of a composition could emmanate within the same performance... The next step, of course, is to improvise the rules themself. (But that would go back to the free jazz idea... ;-)