We are seeing very interesting pattern. A lot of people (including PG in recent interview
http://news.ycombinator.com/item?id=1632477 ) noted that YC founders communicate via Facebook not email. We take this observation to the business - customer world (b2b) and we have created real-time facebook-like communication platform that controls the context (sales business process). Each action fires up an email - but in this case email is just a notification - SMS-like service to let you know that something is going on in the project.