Yes indeed, Meaghan, there is an awful lot to discuss about this topic (I hope you can make it to the meeting on clinical uses of e-mail... see the announcement near the bottom of this page).
One quick idea... Losing one's ISP connection and not being able to receive or send email certainly does create a "black hole" ( http://www.rider.edu/users/suler/psycyber/blackhole.html ) into which clients can project all sorts of fantasies. But, it also reminds me of the notion in self psychology about how grappling with "empathic dysjunctions" can be a major step forward in psychotherapy. Talking about the loss of e-mail contact with the therapist - what it meant to the client, how they experienced it - could be a very therapeutic process.