Hello there
I’m happy coz I have got a cool concept thanks to Kavita Kamani (Program Manager, Connected Framework); everything started when I did the Travel Booking Applicatin example (available from WinFX community site) I found an extensible inteface using; then I got this question: what’s the advantange of doing it by this way and not by referencing directly  the appropiate project ?
I supossed the first advantage it was having a less tightly coupled code but what I really liked knowing it was that this is like a service oriented pattern, I mean, what one does it’s using these activities for generic communications and then implementing deatils for each service which ones will consume them.
Here you can find more on HandleExternalEventActivity & CallExternalMethodActivity:
 Activities:
Cheers
Javier Caceres