I have also recently changed my hard-line stance against UI walkthroughs and heavyhanded cuing, so I'm very receptive to the evolving thoughts of this Pivotal guy.

It's less about walk throughs and more about coach marks, microinteractions, and progressive reduction:

I don’t have all the answers to where that balance lies, but here are a few patterns I hope to borrow heavily from:

Coach Marks

are Apple’s term for specifically guiding a user by pointing out a control/interaction.  Apple actually introduced this in 1995 (!), back when we were all learning a new interface (the GUI).  The main aspect of the coach marks is that they are dimmed out when the appear behind the guide window itself

While they might seem cheesy, they shortcut the cognitive processing somebody performs when looking at a novel interface.

Microinteractions

…which begs the question, “Why are we creating so many new patterns for interaction?”  As Dan Saffer describes in his book, Microinteraction, the limited space plus introductionn of touch and gestures provides the opportunity for ‘Invisible triggers.’  Triggers refer to actions that you initiate while using a product.  An invisible trigger could be hitting the Volume Down button on an iPhone while it’s ringing to mute it.  It turns out that iOS is chock full of these triggers, yet you may never discover them except via trial and error or word of mouth.  App developers have taken a cue from Apple and gone nuts with these (often non-intuitive) gestures.  Which leads me to…

Progressive Reduction

Coined by LayerVault, Progressive Reduction refers to the gradual removal of context as a user becomes an expert.  This screenshot represents a feature they call Signposting:

Within LayerVault, all of your revisions are private. Signposts allow you to pluck revisions from a design’s timeline and expose them to a client or teammate. It’s incredibly useful but also slightly ambiguous at first.

Our Signposting button starts out as a large icon with a label. When you’ve demonstrated proficiency, we remove the label. After you’ve become a total pro, we de-emphasize the button altogether.

LayerVault creates a proficiency profile for every user — when you’re an expert, they get out of the way.