Luke Wroblewski has a thoughtful article on why Sign Up Forms Must Die.

His examples of "gradual engagement" are pragmatic, applied customer experiences that reflect concepts outlined by Rogers and Peppers and many others.

We all deal with Salesforce Web-to-Lead forms on a daily basis, but it's not often that we think of breaking a Lead form down into several smaller forms and seek to gradually learn more about prospects over time.

Granted, most of the examples in Luke's article are in a B2C context, but B2B sites with more than one case study or several pieces of collateral can apply the same concept.