Hard to believe that it's been 15 years ago I posted this recipe. Not surprising is that TVWB is still going strong. I continue to be amazed (amused?) that the #1 Google result for "smoked mushroom dip" all these years later is this thread. And that, today, at least from this locale, the grocery whose smoked mushroom dip I reverse-engineered way-back-when is Google result #2.
It doesn't really bring anything to the final product but texture. It's only in the recipe because it was in the original dip I replicated. Unless you have some other use for pine nuts, which are expensive, just leave it out. I do.