Very true. And vice versa is actually a pretty neat idea. Youngme Moon who I mention in the article has a book called Different which I highly recommend. She's got a bit in there about differentiating yourself by making it insanely easy for people to leave your service. Most folks make it hard to even find a cancel link (I know I've been guilty of this), let alone make it super easy to move their data out into a competitor.
It's on my priority list actually for some future projects to make it super easy to quit and migrate data out of my stuff to a competitor.