I believe we can get people engaged with digital services in a way that tells them how such services work and why they should care enough to use them. I also believe we can do this without explicitly making them fill out a sign-up form as a first step.
An old (2008), but still actual post by Luke Wroblewski about new look at the sign up forms (still a way to go in 2010). He also has a section on gradual engagement solution, which implementation showed nice results in many companies (ie. Twitter).